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Reflectance spectroscopy for recognition
and age determination of bloodstains
Rolf Bremmer and Maurice Aalders
Academic Medical Center
University of Amsterdam
The Netherlands
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This presentation was delivered by
Rolf Bremmer at the annual conference of the
American Academy of Forensic Sciences
in Chicago on February 25 2011
Prelimairy note
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Aim of this talk
Presentation was nominated for Emerging
Forensic Scientist Award
Statement:
I have no financial or
commercial interest
I. Principles of reflectance spectroscopy
II. Bloodstain age determination
III. Discrimination between blood & non-blood
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Can we determine bloodstains at crime scenes
Paint-can, found next to a body at a crime scene
?
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RNA degradation
Bauer et al 2003
ESR
Fujita et al 2005
AFM
Strasser et al 2007
All: confirm changing chemical and physical properties
None: shown precision required for forensic application
Literature on age determination of bloodstains
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I. Principles of reflectance spectroscopy
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Reflectance spectroscopy
• Characterizes color
• Determines hemoglobin in bloodstain
• Non-destructive & results within a second
• Portable and applicable at crime scenes
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Reflectance spectroscopy schematic
1. Light source
2. Fibers
3. Spectrometer
4. Notebook
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Reflectance spectroscopy at the crime scene
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Reflectance spectrum of bloodstain
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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II. Bloodstain age determination
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Hemoglobin in vivo
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
in vivo only 1% of hemoglobin is met-Hb
autoxidation
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Hemoglobin in bloodstains
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
denaturation
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Spectra of hemoglobin
HbO2 met-Hb Hemichrome
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Determine hemoglobin fraction in bloodstain
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
Hemoglobin spectra matched with non-linear least
squares fit to determine fractions of hemoglobin
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Four typical bloodstain reflectance with fit
HbO2 met-Hb HC
1 hour 0.89 0.01 0.10
1 day 0.60 0.05 0.35
7 days 0.35 0.16 0.49
56 days 0.16 0.17 0.66
Table: Fractions of Hb derivatives
based on fits
• • • • bloodstain reflectance
hemoglobin fit
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Hemoglobin in bloodstainsF
raction
(-)
Age (days)
HC
met-Hb
HbO2
Error bars represent
standard deviation
for n = 20.
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+
+
+
-----------------
Age ≈ 9 days
HC=0.53
HbO2=0.32
Met-Hb=0.18
Age determination of bloodstainsF
raction
(-)
Age (days)
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
met-Hb
HbO2
Measured fractions are matched
with typical kinetics to determine age
HC
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Inaccuracy increases with age
Typical Inaccuracy
9 ± 4 days
Disclaimer: Based on white cotton in a laboratory
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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III. Discrimination between
blood and non-blood
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition
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Is it blood?
ketchup
low fit quality
bloodstain
high fit quality
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A lot of red stains
Measured 40 bloodstains and 35 non-bloodstains
Specificity 100% and sensitivity 98%
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stain on paint-can is not blood(absence of blood was confirmed by tetrabase test)
Case report
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Summary
• Reflectance spectroscopy: cheap, non-destructive,
applicable at the crime scene
• Measure fractions of hemoglobin
• Determine age of bloodstain
• Discriminate between blood and non-blood
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Future research
• Determine influence of environment on ageing
• Extend measurements to dark colored
substrates
• Integrate spectroscopic measurement into
camera system
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Publications
• Age estimation of bloodstains by reflectance spectroscopy
Bremmer et al.
Forensic Science International 2011
• Non contact spectroscopic determination of blood volume fractions
Bremmer et al.
Biomedical Optics Express 2011
• Remote spectroscopic identification of bloodstains
Bremmer et al.
Journal of Forensic Science, in print
• Forensic Quest of Age Determination of Bloodstains, a Review
Bremmer et al.
Submitted to Forensic Science International
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Acknowledgements
Annemarie Nadort, MSc
Gerda Edelman, MSc
Martin van Gemert, PhD
Ton van Leeuwen, PhD
Nick Laan MSc
Karla de Bruin PhD
Ted Bijvoets
Rolf Bremmer, MSc
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