Biological Fluid Stain Evidence: Blood and Semen Lum Farr Lum Farr Department Chair – Criminal Justice Department Chair – Criminal Justice Weatherford.

Biological Fluid Stain Biological Fluid Stain Evidence: Blood and SemenEvidence: Blood and Semen

Lum FarrLum Farr Department Chair – Criminal JusticeDepartment Chair – Criminal Justice

Weatherford College ProfessorWeatherford College Professor

Forensic Science & Criminal JusticeForensic Science & Criminal Justice

AuthorAuthorForensic Investigation: behind the yellow tapeForensic Investigation: behind the yellow tape

Co-Founder and PresidentCo-Founder and President

AMERICAN CRIME SCHOOLAMERICAN CRIME SCHOOL

Biological Fluid Stain Biological Fluid Stain Evidence: Blood and SemenEvidence: Blood and Semen

Biological Material must be Biological Material must be considered hazardous!!!considered hazardous!!!

Always follow Universal Precautions Always follow Universal Precautions for handling stains.for handling stains.

Blood and Semen EvidenceBlood and Semen Evidence

Precautions used to collect biological Precautions used to collect biological evidence:evidence:

– Wear latex gloves, surgical masks, and Wear latex gloves, surgical masks, and full coverage gowns.full coverage gowns.

– Eye-coverings are needed for collecting Eye-coverings are needed for collecting liquid samples.liquid samples.

– Keep hand out of areas that are hidden.Keep hand out of areas that are hidden.– Label all blood samplesLabel all blood samples

Blood and Semen EvidenceBlood and Semen Evidence

– Package dry samples in bags, as well as Package dry samples in bags, as well as stained clothing.stained clothing.

– Add a note of precaution if biohazards Add a note of precaution if biohazards like AIDS or hepatitis are suspected.like AIDS or hepatitis are suspected.

– Decontaminate all non-disposable items.Decontaminate all non-disposable items.– Destroy tags, forms, or reports splashed Destroy tags, forms, or reports splashed

with blood.with blood.– Clean up hands with diluted bleach, and Clean up hands with diluted bleach, and

dispose of contaminated clothing.dispose of contaminated clothing.

Biological Fluid Stain Biological Fluid Stain Evidence: Blood and SemenEvidence: Blood and Semen The term Universal Precautions The term Universal Precautions

means:means:

One must assume that any biological One must assume that any biological material is contaminated with material is contaminated with biological pathogens such as HIV, biological pathogens such as HIV, Hepatitis B, or others.Hepatitis B, or others.

– Always use protective clothing, eyewear, Always use protective clothing, eyewear, respirator masks, latex gloves, etc.respirator masks, latex gloves, etc.

Nature of Blood EvidenceNature of Blood Evidence

Blood may be encountered as Blood may be encountered as physical evidence in:physical evidence in:

– HomicidesHomicides– Sexual AssaultSexual Assault– Vehicular hit-and-runVehicular hit-and-run– BurglaryBurglary– Other crimesOther crimes

Bloodstain CharacteristicsBloodstain Characteristics

Traditional steps to follow in trying to Traditional steps to follow in trying to describe various tests conducted:describe various tests conducted:

– Is the sample blood?Is the sample blood?– Is the sample animal blood?Is the sample animal blood?– If animal blood, from what species?If animal blood, from what species?– If human blood, what type?If human blood, what type?– Can the sex, age, and race be Can the sex, age, and race be

determined?determined?

Preliminary ConsiderationsPreliminary Considerations

It is essential to document, collect, It is essential to document, collect, and preserve blood evidence.and preserve blood evidence.

Improperly collected and preserved Improperly collected and preserved blood evidence can weaken or blood evidence can weaken or destroy a potential source of facts in destroy a potential source of facts in a case.a case.


Properly collected and preserved Properly collected and preserved blood evidence can establish a blood evidence can establish a strong link between an individual and strong link between an individual and a criminal act.a criminal act.

Blood evidence or the lack of blood Blood evidence or the lack of blood evidence can bolster or contradict a evidence can bolster or contradict a witness statement or any statements witness statement or any statements the suspect may have made.the suspect may have made.


Blood evidence can point the Blood evidence can point the investigator in the right direction for investigator in the right direction for investigative purposesinvestigative purposes

If the evidence is collected and If the evidence is collected and stored suitably, it can be presented stored suitably, it can be presented to a judge or jury several years from to a judge or jury several years from the time of the criminal act.the time of the criminal act.


Perhaps the most powerful Perhaps the most powerful application of blood evidence application of blood evidence is the ability to absolutely is the ability to absolutely eliminate a person as a eliminate a person as a potential suspect in a crime.potential suspect in a crime.


Communication is the key to effectively Communication is the key to effectively processing blood evidence.processing blood evidence.

Clear and open communication must exist Clear and open communication must exist between a crime scene’s first responding between a crime scene’s first responding officer, the case detective, the crime officer, the case detective, the crime scene investigator, the forensic scientist scene investigator, the forensic scientist analyzing the evidence and the assistant analyzing the evidence and the assistant district attorney handling the case.district attorney handling the case.


A crime scene investigator should A crime scene investigator should know the crime lab’s capabilities, the know the crime lab’s capabilities, the methods of blood collection and methods of blood collection and preservation preferred by the crime preservation preferred by the crime lab, the investigative information lab, the investigative information relevant to the forensic scientist, and relevant to the forensic scientist, and the type of reference samples the type of reference samples required by the crime lab.required by the crime lab.


This information can and will change This information can and will change periodically as technology changes, periodically as technology changes, lab policies change, lab personnel lab policies change, lab personnel change, or lab administrations change, or lab administrations change.change.

The preference of forensic scientists The preference of forensic scientists also very from lab to lab.also very from lab to lab.


In the early 1970’s most crime labs In the early 1970’s most crime labs relied upon the ABO blood grouping relied upon the ABO blood grouping system to characterize bloodstains.system to characterize bloodstains.

This meant that the blood could have This meant that the blood could have come from 4 to 49% of the come from 4 to 49% of the population.population.


In the 1990’s, most crime labs In the 1990’s, most crime labs starting relying on DNA analysis to starting relying on DNA analysis to characterize bloodstains.characterize bloodstains.

A blood source can now be A blood source can now be statistically narrowed down to one statistically narrowed down to one person out of several million or even person out of several million or even several billion.several billion.


A crime scene investigator should A crime scene investigator should know which method or methods of know which method or methods of bloodstain analysis are available bloodstain analysis are available from his or her crime lab, the FBI lab, from his or her crime lab, the FBI lab, and private labs in the community.and private labs in the community.


Currently bloodstain analysis falls Currently bloodstain analysis falls into three broad categories:into three broad categories:

1) Conventional Serological Analysis:1) Conventional Serological Analysis:– Analysis of the proteins, enzymes, and Analysis of the proteins, enzymes, and

antigens present in the blood.antigens present in the blood.


– These substances are more These substances are more susceptible to degradation than DNA susceptible to degradation than DNA and this type of testing usually and this type of testing usually requires a “large” (quarter size) requires a “large” (quarter size) sample in good condition for optimal sample in good condition for optimal results.results.

– This type of testing is rarely This type of testing is rarely statistically individualizing.statistically individualizing.


2) Restriction Fragment Length 2) Restriction Fragment Length Polymorphism (RFLP) DNA AnalysisPolymorphism (RFLP) DNA Analysis

– Direct analysis of certain DNA sequences Direct analysis of certain DNA sequences present in the white blood cells.present in the white blood cells.

– DNA is much less susceptible to DNA is much less susceptible to degradation than proteins, enzymes, degradation than proteins, enzymes, and antigens.and antigens.


– RFLP DNA testing is commonly RFLP DNA testing is commonly statistically individualizing (one out of statistically individualizing (one out of several million or billion) and it has several million or billion) and it has withstood rigorous court challenges on withstood rigorous court challenges on its validity.its validity.

– This method also usually requires a This method also usually requires a “large” sample size to obtain significant “large” sample size to obtain significant results.results.


3) Polymerase Chain Reaction (PCR) 3) Polymerase Chain Reaction (PCR) DNA Analysis:DNA Analysis:

– Analysis of certain DNA sequences that Analysis of certain DNA sequences that have been copied multiple times to a have been copied multiple times to a detectable level. detectable level.

– PCR based testing works well on degraded PCR based testing works well on degraded samples and “small” samples (pinhead samples and “small” samples (pinhead size).size).


– Currently, it is not as statistically Currently, it is not as statistically individualizing as RFLP analysis.individualizing as RFLP analysis.

– PCR based technologies have also PCR based technologies have also withstood rigorous court challenges on withstood rigorous court challenges on its validity.its validity.

– Recently there has been some concerns Recently there has been some concerns over the possibility of incidental over the possibility of incidental contamination giving false results.contamination giving false results.


– Following PCR protocols should help Following PCR protocols should help eliminate contamination thereby, eliminate contamination thereby, eliminating false results.eliminating false results.

– The only way that false results were The only way that false results were reduced during studies, was by direct reduced during studies, was by direct cross contamination of wet samples.cross contamination of wet samples.


Presently, the courts do not recognize Presently, the courts do not recognize blood evidence as evidence that can be blood evidence as evidence that can be absolutely linked to an individual, such as absolutely linked to an individual, such as fingerprints, bite marks, broken fingernails, fingerprints, bite marks, broken fingernails, and handwriting.and handwriting.

If DNA analysis is utilized, then blood If DNA analysis is utilized, then blood evidence falls into the category of evidence evidence falls into the category of evidence that can be linked to an individual with a that can be linked to an individual with a very very high degree of probability.high degree of probability.


RFLP DNA Analysis has been given RFLP DNA Analysis has been given the misnomer “DNA Fingerprinting.” the misnomer “DNA Fingerprinting.”

The courts have since ruled that a The courts have since ruled that a DNA results can only be given in DNA results can only be given in statistical terms.statistical terms.


A Forensic Scientist cannot testify that a A Forensic Scientist cannot testify that a bloodstain came from a specific bloodstain came from a specific individual.individual.

– He/she can testify that based on population He/she can testify that based on population studies, only one person in several million or studies, only one person in several million or billion has a particular DNA profile.billion has a particular DNA profile.

– He/she can then testify if the suspect or a He/she can then testify if the suspect or a victim has that DNA profile.victim has that DNA profile.


Before a crime scene investigator Before a crime scene investigator begins documenting and collecting begins documenting and collecting blood evidence, he/she must blood evidence, he/she must recognize the value of blood recognize the value of blood evidence and how it fits in the overall evidence and how it fits in the overall events associated with the crime.events associated with the crime.


The most common applications of The most common applications of blood evidence are:blood evidence are:

– Finding blood with the victim’s genetic Finding blood with the victim’s genetic markers (ABO blood type, DNA profile, markers (ABO blood type, DNA profile, etc) on the suspect, on something in the etc) on the suspect, on something in the suspect’s possession, or something suspect’s possession, or something associated with the suspect (such as the associated with the suspect (such as the suspect’s fingerprints).suspect’s fingerprints).


– Finding blood with the suspect’s genetic Finding blood with the suspect’s genetic markers on the victim, on something in markers on the victim, on something in the victim’s possession, or something the victim’s possession, or something associated with the victim.associated with the victim.


Occasionally, investigator’s blindly collect Occasionally, investigator’s blindly collect blood samples from a scene without any blood samples from a scene without any thought about the facts they are trying to thought about the facts they are trying to establish or the tests that will be establish or the tests that will be forthcoming with the blood evidence.forthcoming with the blood evidence.

The CSI must make an effort to collect the The CSI must make an effort to collect the evidence that is going to provide the most evidence that is going to provide the most useful information in establishing the facts useful information in establishing the facts about a crime scene.about a crime scene.

BloodspatterBloodspatter


The CSI should concentrate on collecting The CSI should concentrate on collecting samples of “peripheral” bloodstains.samples of “peripheral” bloodstains.

– Blood away from the body and the main Blood away from the body and the main area of action.area of action.

– Blood spatter patterns that differ from the Blood spatter patterns that differ from the majority of the blood spatter patterns.majority of the blood spatter patterns.

– Blood trails leading away from the scene.Blood trails leading away from the scene.

Peripheral Bloodstains Away Peripheral Bloodstains Away from Bodyfrom Body

Bloodspatter patterns that Bloodspatter patterns that look different at the crime look different at the crime

scenescene

Blood Trails Away From Blood Trails Away From BodyBody

Preliminary ConsiderationsPreliminary Considerations Because blood analysis is a comparison Because blood analysis is a comparison

analysis, reference blood samples are analysis, reference blood samples are needed from the victim and suspect.needed from the victim and suspect.

A comparison must be made between the A comparison must be made between the genetic markers in the victim’s blood and genetic markers in the victim’s blood and the suspect’s blood.the suspect’s blood.

The blood samples from the crime scene The blood samples from the crime scene can then be analyzed for genetic markers can then be analyzed for genetic markers that are different in the suspect and that are different in the suspect and victim.victim.


Suitable reference samples must be Suitable reference samples must be collected from all involved and sent collected from all involved and sent to the crime lab.to the crime lab.

An unsuitable reference sample is An unsuitable reference sample is bloody clothing or some other bloody bloody clothing or some other bloody item.item.


These are unsuitable because of the These are unsuitable because of the questionable histories of the stains questionable histories of the stains and there may be factors present on and there may be factors present on the items that will give misleading the items that will give misleading results.results.

Samples must be collected in Samples must be collected in suitable “Vacutainers.”suitable “Vacutainers.”


Vacutainer usage:Vacutainer usage:

Yellow Top V.Yellow Top V.– Useful for conventional serological Useful for conventional serological

testing and DNA testing. (personal testing and DNA testing. (personal preference)preference)

Purple Top V.Purple Top V.Useful for DNA testing; may inhibit Useful for DNA testing; may inhibit certain conventional serological tests.certain conventional serological tests.


Red Top V.Red Top V.

Useful for conventional serological tests:Useful for conventional serological tests:

Less useful for DNA testing:Less useful for DNA testing:

Can be used for pregnancy and HIV Can be used for pregnancy and HIV testing:testing:

Gray Top V.Gray Top V.

Useful for toxicological testing;Useful for toxicological testing;

Not suitable for conventional serological Not suitable for conventional serological analysisanalysis

May not be suitable for DNA analysisMay not be suitable for DNA analysis


If collecting blood from an Autopsy, If collecting blood from an Autopsy, collect one of each type of collect one of each type of Vacutainer.Vacutainer.

– Should be stored in a refrigerator (not Should be stored in a refrigerator (not frozen) at about four degrees frozen) at about four degrees Centigrade until transported to the Centigrade until transported to the crime lab.crime lab.

Bloodspatter PatternsBloodspatter PatternsProjected BloodProjected Blood

Bloodspatter Patterns Blood Bloodspatter Patterns Blood droplets from different droplets from different

anglesangles

Passive Blood DropletsPassive Blood Droplets

Transfer Blood PatternTransfer Blood Pattern

Transfer BloodstainsTransfer Bloodstains

Passive Bloodstain from a Passive Bloodstain from a WeaponWeapon

Dripped BloodDripped Blood

Spilled BloodSpilled Blood

Projected Blood through a Projected Blood through a SyringeSyringe

Arterial Spurt/GushArterial Spurt/Gush

Cast-Off StainsCast-Off Stains

Impact Spatter – Low Impact Spatter – Low VelocityVelocity

Medium VelocityMedium Velocity

High VelocityHigh Velocity

Blood Evidence Problems:Blood Evidence Problems:

Communication between CSI and FSCommunication between CSI and FS Unfamiliarity with the types of Unfamiliarity with the types of

bloodstain analysisbloodstain analysis Lack of knowledge about which Lack of knowledge about which

stains will yield the most useful stains will yield the most useful information.information.

Poor reference samples.Poor reference samples. Indiscriminately using Luminol at CS.Indiscriminately using Luminol at CS.


The identity and typing of bloodstains canThe identity and typing of bloodstains can– Assist in establishing elements of the crimeAssist in establishing elements of the crime– Can identify or eliminate a suspectCan identify or eliminate a suspect– Can be used to corroborate or dispute the Can be used to corroborate or dispute the

statements of principals when the bloodstains statements of principals when the bloodstains play a part in a reconstruction of the crime.play a part in a reconstruction of the crime.

– The proper collection is essential to the The proper collection is essential to the quantity and the quality of information from quantity and the quality of information from the stainsthe stains


Bloodstain evidence has two primary Bloodstain evidence has two primary categories of examination categories of examination importance to the crime scene importance to the crime scene investigator:investigator:

– A. Bloodstain pattern interpretationA. Bloodstain pattern interpretation

– B. Genetic Marker TypingB. Genetic Marker Typing

Blood Pattern InterpretationBlood Pattern Interpretation

Often overlooked by both the Often overlooked by both the investigator and the laboratory investigator and the laboratory personnel.personnel.

In many cases the blood pattern In many cases the blood pattern interpretation is more significant interpretation is more significant than the typing of the stains.than the typing of the stains.


May establish whether or not a crime May establish whether or not a crime occurred (murder vs. suicide or occurred (murder vs. suicide or accident)accident)

May dispute or corroborate witnesses’ May dispute or corroborate witnesses’ statements.statements.

Can determined from whom the Can determined from whom the bloodstain pattern emanated. (genetic bloodstain pattern emanated. (genetic marker typing)marker typing)


Proper documentation of the location Proper documentation of the location and patterns of the bloodstains should and patterns of the bloodstains should always be a primary consideration of always be a primary consideration of the crime scene investigator at a the crime scene investigator at a crime scene.crime scene.

Collection should NOT be attempted Collection should NOT be attempted until the patterns have been until the patterns have been recorded.recorded.


All bloodstains should be recorded:All bloodstains should be recorded:– In the Investigators NotesIn the Investigators Notes

– There should be crime scene sketchesThere should be crime scene sketches

– There should be photographsThere should be photographs

This will prevent a later attempt to This will prevent a later attempt to interpret the pattern without proper interpret the pattern without proper documentation.documentation.


The location, size, and The location, size, and appearance of the patterns appearance of the patterns must be carefully measured, must be carefully measured, sketched, and photographed sketched, and photographed with measuring scales in the with measuring scales in the photographs.photographs.


Videotaping blood evidence can show Videotaping blood evidence can show the overall blood spatter patterns and the overall blood spatter patterns and how these spatters are inter related.how these spatters are inter related.

Videotaping can show the relationship Videotaping can show the relationship of the spatters to the various of the spatters to the various structures at the crime scene.structures at the crime scene.


Videotaping can be used to document Videotaping can be used to document any blood trails leading away from the any blood trails leading away from the scene.scene.

Indoors videotaping can show how the Indoors videotaping can show how the various areas are laid out in relation to various areas are laid out in relation to each other and how they can be each other and how they can be accessed.accessed.– Valuable when recording peripheral Valuable when recording peripheral

bloodstainsbloodstains


It is absolutely essential that still It is absolutely essential that still photos be taken.photos be taken.

When available use, color When available use, color prints/slides and black & white film.prints/slides and black & white film.

Infrared film can also be used for Infrared film can also be used for documenting bloodstains on dark documenting bloodstains on dark surfaces.surfaces.


A good technique for recording large areas A good technique for recording large areas of blood spatter on a wall:of blood spatter on a wall:

– Measure and record the heights of some of the Measure and record the heights of some of the individual blood spatters.individual blood spatters.

– Photograph the overall blood spatter with slide Photograph the overall blood spatter with slide film using a yard stick as a measuring device.film using a yard stick as a measuring device.

– Can be projected onto a blank wall or the Can be projected onto a blank wall or the original wall later after cleanup.original wall later after cleanup.

Impact Angle of Blood Impact Angle of Blood DropletDroplet

Impact Angle of Blood Impact Angle of Blood Droplet 2-dimensional planeDroplet 2-dimensional plane


Always draw a CS sketch.Always draw a CS sketch.

– Photos are 2-dimensionalPhotos are 2-dimensional

– The CS is 3-dimensionalThe CS is 3-dimensional

– Photos can distort spatial relationshipsPhotos can distort spatial relationships

Computer programs are now available for Computer programs are now available for sketching.sketching.


Chain-of-Custody form.Chain-of-Custody form.

It is a written record of all evidence It is a written record of all evidence transfers from the CS to possession of the transfers from the CS to possession of the court or the clerk of court.court or the clerk of court.

The Chain-of-Custody thoroughly The Chain-of-Custody thoroughly documents the movement of evidence, the documents the movement of evidence, the security of evidence, who had possession security of evidence, who had possession of the evidence, and when the evidence of the evidence, and when the evidence was in a person’s possession.was in a person’s possession.

Luminol TestingLuminol Testing

Luminol is a visualization enhancing Luminol is a visualization enhancing chemical.chemical.

– When applied to bloodstains, even very When applied to bloodstains, even very diluted bloodstains, will cause the diluted bloodstains, will cause the bloodstains to glow in the dark.bloodstains to glow in the dark.

– Drawbacks – should be a last resort for Drawbacks – should be a last resort for the CSIthe CSI


The Problems with Luminol:The Problems with Luminol:

– One of the empirical tests for determining if One of the empirical tests for determining if a stain is blood is its appearance.a stain is blood is its appearance.

– If it is a bloodstain, it should look like blood.If it is a bloodstain, it should look like blood.

– Blood should be present in sufficient Blood should be present in sufficient quantity to perform confirmatory testing quantity to perform confirmatory testing and genetic markers.and genetic markers.


Luminol is, at best, a presumptive Luminol is, at best, a presumptive test for blood.test for blood.

If the stain is so dilute that it can If the stain is so dilute that it can only be visualized with luminol, then only be visualized with luminol, then no further analysis can be performed no further analysis can be performed to confirm the presence of blood.to confirm the presence of blood.


Luminol will give false reactions.Luminol will give false reactions.– Can react with copper ions, copper Can react with copper ions, copper

compounds, iron compounds, and cobalt compounds, iron compounds, and cobalt ions.ions.

– It will react with potassium permangante It will react with potassium permangante (found in some dyes) and hydrated sodium (found in some dyes) and hydrated sodium hypochlorite (bleach).hypochlorite (bleach).

– Ferricyanide and plant peroxidases could Ferricyanide and plant peroxidases could also give false reactions.also give false reactions.


Studies have shown that luminol will cause Studies have shown that luminol will cause the loss of several genetic markers.the loss of several genetic markers.

– Because luminol is water based, it could Because luminol is water based, it could cause, latent, possibly bloody impression to cause, latent, possibly bloody impression to smear.smear.

– Luminol could also further dilute an already Luminol could also further dilute an already diluted stain. This may push the stain diluted stain. This may push the stain beyond the gentic marker analysis detection beyond the gentic marker analysis detection limits.limits.


Unfortunately some crime scenes use Unfortunately some crime scenes use Luminol as their first choice for Luminol as their first choice for detecting blood.detecting blood.

– This could cause loss of valuable This could cause loss of valuable information from a bloodstain.information from a bloodstain.

– First choice should be high intensity First choice should be high intensity light.light.


Bloodstains are not easy to eradicate.Bloodstains are not easy to eradicate. Diluted blood will often leave a brownish Diluted blood will often leave a brownish

stain when cleanup is attempted.stain when cleanup is attempted.

Has a tendency to flow into floorboards Has a tendency to flow into floorboards cracks, carpet padding, behind cracks, carpet padding, behind baseboards, etc.baseboards, etc.

These can usually be found using a high These can usually be found using a high intensity light.intensity light.


Because Luminol is so sensitive to Because Luminol is so sensitive to bloodstains, it is occasionally used to bloodstains, it is occasionally used to enhance bloody impressions enhance bloody impressions (shoeprint, fingerprint, etc).(shoeprint, fingerprint, etc).

Not the best method however, Not the best method however, because it is water-based.because it is water-based.

Collection and Preservation Collection and Preservation of Blood Evidenceof Blood Evidence

Most items of blood evidence will be Most items of blood evidence will be collected in clean, unused paper collected in clean, unused paper containers such as packets, containers such as packets, envelopes, and bags.envelopes, and bags.

– Can use plastic containers for up to 2-Can use plastic containers for up to 2-hours.hours. I do not recommend any plastic containers.I do not recommend any plastic containers.


Key note: Key note:

– Do not allow any evidence, especially Do not allow any evidence, especially blood evidence to become contaminated blood evidence to become contaminated with other evidence at the crime scene with other evidence at the crime scene or during transportation to the crime lab.or during transportation to the crime lab.

– Remove blood evidence from the CS Remove blood evidence from the CS immediately and if wet allow to air dry at immediately and if wet allow to air dry at room temperature.room temperature.


UNDER NO CIRCUMSTANCES SHOULD UNDER NO CIRCUMSTANCES SHOULD EVIDENCE CONTAINING MOISTURE EVIDENCE CONTAINING MOISTURE BE SEALED IN PLASTIC OR PAPER BE SEALED IN PLASTIC OR PAPER CONTAINERS FOR MORE THAN TWO CONTAINERS FOR MORE THAN TWO HOURS. HOURS.

– Moisture allows the growth of Moisture allows the growth of microorganism that can destroy or alter microorganism that can destroy or alter evidence.evidence.


Any evidence that can cross Any evidence that can cross contaminate each other must be contaminate each other must be packaged separately.packaged separately.

Containers should be closed and Containers should be closed and secured to prevent the mixture of secured to prevent the mixture of evidence during transportation.evidence during transportation.


Each container should have the Each container should have the collecting person’s initials, the date collecting person’s initials, the date and time it was collected, a complete and time it was collected, a complete description of the evidence and description of the evidence and where it was found, and the where it was found, and the investigating agency’s name and file investigating agency’s name and file number/case number.number/case number.


Before transporting, examine the Before transporting, examine the items to determine if there is any items to determine if there is any loose trace evidence (hairs, fibers, loose trace evidence (hairs, fibers, paint chips, etc) that may be lost in paint chips, etc) that may be lost in transportation.transportation.

Collect this evidence in a paper Collect this evidence in a paper packet and place in an envelope.packet and place in an envelope.– Give description that matches the Give description that matches the

original evidence where collected.original evidence where collected.


Blood evidence must never be Blood evidence must never be exposed to heat or humidity. exposed to heat or humidity.

If possible, always refrigerate until it If possible, always refrigerate until it can be transported.can be transported.

Take blood evidence to the lab as Take blood evidence to the lab as soon as possible.soon as possible.

Collecting Dried BloodstainsCollecting Dried Bloodstains

If small and transportable, package it.If small and transportable, package it.– AdvantageAdvantage

Minimal interaction with stain by investigator.Minimal interaction with stain by investigator. Allows serologist to make the decisions involved Allows serologist to make the decisions involved

in collecting the samplesin collecting the samples Dilution and contamination potential minimized Dilution and contamination potential minimized

by eliminating water as the collection medium.by eliminating water as the collection medium.

– Disadvantage:Disadvantage: Bulky items require more storage space.Bulky items require more storage space.


Large Items with stains:Large Items with stains:– Cut out a portion of the item with the Cut out a portion of the item with the

stain.stain.– Cut out sample portion away from stain.Cut out sample portion away from stain.

– Advantage: Dilution and contamination Advantage: Dilution and contamination minimized.minimized.

– Disadvantage: Must decide which stains Disadvantage: Must decide which stains and controls to collect.and controls to collect.


Tape Lifting Bloodstain:Tape Lifting Bloodstain:– AdvantageAdvantage

Dilution and contamination potential Dilution and contamination potential minimized.minimized.

Negative control is readily collected.Negative control is readily collected. Requires little storage spaceRequires little storage space Easy to performEasy to perform

– DisadvantageDisadvantage Must decide which stains to collect.Must decide which stains to collect.


Scraping bloodstains into a paper Scraping bloodstains into a paper packet:packet:– AdvantageAdvantage

Dilution and contamination potential minimized.Dilution and contamination potential minimized.

– DisadvantageDisadvantage Must decide which stains to collectMust decide which stains to collect Stains tend to break into small, hard to handle Stains tend to break into small, hard to handle

flakesflakes Flakes tend to get lost easily.Flakes tend to get lost easily. Some surfaces are not easily scraped.Some surfaces are not easily scraped.


Absorbing stains onto moist ½” long Absorbing stains onto moist ½” long threadsthreads– AdvantageAdvantage

Stains are concentrated onto a small areas.Stains are concentrated onto a small areas. Requires little storage spaceRequires little storage space

– DisadvantageDisadvantage Dilution and contamination problem Dilution and contamination problem

increases.increases. Must decide which stain to collect.Must decide which stain to collect. 70% ethanol is best to use as a dilution.70% ethanol is best to use as a dilution.


Absorbing onto moist ½ X ½ Cotton Absorbing onto moist ½ X ½ Cotton SquareSquare– AdvantageAdvantage

Stain on small area.Stain on small area. Easier to handle than treadsEasier to handle than treads Requires little storage spaceRequires little storage space

– DisadvantageDisadvantage Dilution and contamination potential Dilution and contamination potential

increased.increased.

Wet BloodstainsWet Bloodstains

If the item is small:If the item is small:– Package in paper bag.Package in paper bag.– Bring to a secured locationBring to a secured location– Take it out of bag and allow to air dry.Take it out of bag and allow to air dry.– Repackage in original bag.Repackage in original bag.– May then place in additional dry bag.May then place in additional dry bag.


Advantage:Advantage: Requires minimal amount of interaction with Requires minimal amount of interaction with

stain.stain.

DisadvantageDisadvantage More work for serologistMore work for serologist

Bulky items take more storage roomBulky items take more storage room..


Large Items:Large Items:– AdvantageAdvantage

Requires little storage.Requires little storage. Fairly easy technique to performFairly easy technique to perform Stain concentrated onto small surface area.Stain concentrated onto small surface area.

– DisadvantageDisadvantage Must decide which stains and controls to Must decide which stains and controls to

collectcollect Must have direct interaction with bloodstainMust have direct interaction with bloodstain

BloodstainsBloodstains

Wet blood has more value than dried Wet blood has more value than dried blood because more tests can be run.blood because more tests can be run.– Blood begins to dry after 3 – 5 minutes of Blood begins to dry after 3 – 5 minutes of

exposure to air.exposure to air.

– As it dries, it changes color towards Brown or As it dries, it changes color towards Brown or black.black.

– Blood at a crime scene can be in the form of Blood at a crime scene can be in the form of pools, drops, smears, or crusts.pools, drops, smears, or crusts.


– Pools of blood have more evidentiary Pools of blood have more evidentiary value.value.

– Drops of blood tell the height and angle Drops of blood tell the height and angle from which the blood fell.from which the blood fell.

– Blood that falls perpendicular to the Blood that falls perpendicular to the floor from a distance of 0 – 2 feet would floor from a distance of 0 – 2 feet would make a circular drop with slightly frayed make a circular drop with slightly frayed edges.edges.

– Drops from a higher distance would Drops from a higher distance would have more pronounced tendrils fraying have more pronounced tendrils fraying off the edges (sunburst pattern).off the edges (sunburst pattern).


– A blood smear on the wall or floor tells A blood smear on the wall or floor tells the direction of force of the blow.the direction of force of the blow.

– The direction of force is always in the The direction of force is always in the direction towards the tail, or small end, direction towards the tail, or small end, of the smear, or splatter.of the smear, or splatter.

– In other words, the largest area of the In other words, the largest area of the smear is the point of origin. (wave cast-smear is the point of origin. (wave cast-off pattern).off pattern).

– Blood crusts need to be tested with Blood crusts need to be tested with crystalline methods to make sure it’s crystalline methods to make sure it’s blood.blood.


Refrigerated red blood cells have a Refrigerated red blood cells have a shelf life of about 42 days.shelf life of about 42 days.

The serum containing white blood The serum containing white blood cells can be refrigerated much cells can be refrigerated much longer, almost up to a year.longer, almost up to a year.


DNA can be extracted from DNA can be extracted from blood (if white blood cells blood (if white blood cells which always contain a which always contain a nucleus are present) and nucleus are present) and also from sperm, bone also from sperm, bone marrow, tooth pulp, and marrow, tooth pulp, and hair roots.hair roots.

Blood Pattern AnalysisBlood Pattern Analysis

Importance in the reconstruction of many Importance in the reconstruction of many crime Scenes:crime Scenes:

– Indicates how the blood was projected from the Indicates how the blood was projected from the body via several factors.body via several factors. Type of injuriesType of injuries The order in which the wounds were receivedThe order in which the wounds were received Whose blood is presentWhose blood is present The type of weapon that caused the injuriesThe type of weapon that caused the injuries Whether the victim was moved after the injury.Whether the victim was moved after the injury. How far the blood drops fell before hitting an object.How far the blood drops fell before hitting an object.


Blood may be dripped out, sprayed Blood may be dripped out, sprayed from an artery, oozed out through a from an artery, oozed out through a large wound, or flung off a weapon large wound, or flung off a weapon raised to strike another blow.raised to strike another blow.

In the 1930’s, Scottish pathologist In the 1930’s, Scottish pathologist John Glaister classified blood John Glaister classified blood splashes into six distinct types.splashes into six distinct types.


Drops on a horizontal surfaceDrops on a horizontal surface Splashes, from blood flying through Splashes, from blood flying through

the air and hitting a surface at an the air and hitting a surface at an angle.angle.

Pools around the body, which can Pools around the body, which can show if it’s been dragged.show if it’s been dragged.

Spurts from a major artery or veinSpurts from a major artery or vein Smears left by movement of a Smears left by movement of a

bleeding personbleeding person


““Bloodstain pattern will help the Bloodstain pattern will help the investigators understand the positions investigators understand the positions and means by which the victim and and means by which the victim and suspect moved, interacted, and suspect moved, interacted, and struggled through the crime scene.struggled through the crime scene.

Helps to prevent an overabundance of Helps to prevent an overabundance of redundant blood samples for DNA.redundant blood samples for DNA.


The shape of the blood drop can reveal The shape of the blood drop can reveal significant information.significant information.

General rule of thumb for smooth, non-General rule of thumb for smooth, non-porous surface might be:porous surface might be:Blood falls short distance – 12” at 90-Blood falls short distance – 12” at 90-deg. Angle, the marks tend to be deg. Angle, the marks tend to be circular.circular.Fall several feet straight down, edges Fall several feet straight down, edges may become crenellated – more may become crenellated – more distance more crenellation.distance more crenellation.

Blood Pattern AnalysisBlood Pattern Analysis Falls 6’ or more can produce small spurts that radiate Falls 6’ or more can produce small spurts that radiate

out from the main drop.out from the main drop.

Many drops less than an eighth of an inch across, Many drops less than an eighth of an inch across, with no larger drop, then it may be concluded that with no larger drop, then it may be concluded that the blood spatter probably resulted from an impact.the blood spatter probably resulted from an impact.

If the source was in motion when the blood leaked or If the source was in motion when the blood leaked or spurted, or if the drops flew through the air and hit spurted, or if the drops flew through the air and hit an angled surface, the drops generally look like an angled surface, the drops generally look like stretched-out exclamation marks. The end of the stretched-out exclamation marks. The end of the stain with smallest blob indicates the direction in stain with smallest blob indicates the direction in which the source was moving.which the source was moving.


Leading Authority on blood stain Leading Authority on blood stain Interpretation gives the following tips:Interpretation gives the following tips:

– It is possible to determine the impact angle of It is possible to determine the impact angle of blood on a flat surface by measuring the blood on a flat surface by measuring the degree of circular distortion of the stain. In degree of circular distortion of the stain. In other words, the shape of the stain tends to other words, the shape of the stain tends to change depending upon the angle of impact change depending upon the angle of impact which caused the stain. For example, the more which caused the stain. For example, the more the angle decreases, the more the stain is less the angle decreases, the more the stain is less circular and more long.circular and more long.


– Surface texture is one of the key components Surface texture is one of the key components in determining spatter type. The harder the in determining spatter type. The harder the surface is, the more spatter will result. It is surface is, the more spatter will result. It is therefore extremely important to duplicate the therefore extremely important to duplicate the surface in a controlled test.surface in a controlled test.

– When a droplet of blood hits a surface which is When a droplet of blood hits a surface which is hard as well as smooth, the blood usually hard as well as smooth, the blood usually breaks apart upon impact. This in turn causes breaks apart upon impact. This in turn causes smaller droplets. The smaller droplets will smaller droplets. The smaller droplets will continue to move in the same direction as the continue to move in the same direction as the original droplet.original droplet.

American Crime SchoolAmerican Crime School

For More Information – ContactFor More Information – Contact

Lum Farr – PresidentLum Farr – President American Crime SchoolAmerican Crime School 817-598-6312 – Office817-598-6312 – Office 817-307-4732 – Cell817-307-4732 – Cell [email protected]@wc.edu

Biological Fluid Stain Evidence: Blood and Semen Lum Farr Lum Farr Department Chair – Criminal Justice Department Chair – Criminal Justice Weatherford.

Documents

nature of blood evidence

preserved blood evidence

biological evidence

lack of blood evidence

blood samples

sample blood

human blood

physical evidence