Presentation given at AAFS 2011 on bloodstain identification and age determination of bloodstains

1. Reflectance spectroscopy for recognition
and age determination of bloodstains
Rolf Bremmer and Maurice Aalders
Academic Medical Center
University of Amsterdam
The Netherlands 1/27

2. Prelimairy note
This presentation was delivered by
Rolf Bremmer at the annual conference of the
American Academy of Forensic Sciences
in Chicago on February 25 2011
2/27

3. Aim of this talk
I. Principles of reflectance spectroscopy
II. Bloodstain age determination
III. Discrimination between blood & non-blood
Statement: Presentation was nominated for Emerging
Forensic Scientist Award
I have no financial or
commercial interest
3/27

4. Can we determine bloodstains at crime scenes
?
Paint-can, found next to a body at a crime scene
4/27

5. Literature on age determination of bloodstains
RNA degradation ESR AFM
Bauer et al 2003 Fujita et al 2005 Strasser et al 2007
All: confirm changing chemical and physical properties
None: shown precision required for forensic application
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6. I. Principles of reflectance spectroscopy
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 6/27

7. 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 7/27

8. Reflectance spectroscopy schematic
1. Light source
2. Fibers
3. Spectrometer
4. Notebook
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9. Reflectance spectroscopy at the crime scene
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 9/27

10. Reflectance spectrum of bloodstain
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 10/27

11. II. Bloodstain age determination
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 11/27

12. Hemoglobin in vivo
autoxidation
in vivo only 1% of hemoglobin is met-Hb
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 12/27

13. Hemoglobin in bloodstains
denaturation
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14. Spectra of hemoglobin
HbO2 met-Hb Hemichrome
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15. Determine hemoglobin fraction in bloodstain
Hemoglobin spectra matched with non-linear least
squares fit to determine fractions of hemoglobin
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 15/27

16. Four typical bloodstain reflectance with fit
•••• bloodstain reflectance
hemoglobin 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
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 16/27

17. Hemoglobin in bloodstains
HbO2
Fraction (-)
HC
Error bars represent
standard deviation
for n = 20.
met-Hb
Age (days)
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 17/27

18. Age determination of bloodstains
HbO2
Fraction (-)
HC
Measured fractions are matched
with typical kinetics to determine age
+ HC=0.53
+ HbO2=0.32
+ Met-Hb=0.18
met-Hb
-----------------
Age ≈ 9 days
Age (days)
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 18/27

19. Inaccuracy increases with age
Typical Inaccuracy
9 ± 4 days
Disclaimer: Based on white cotton in a laboratory
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 19/27

20. III. Discrimination between
blood and non-blood
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21. Is it blood?
bloodstain ketchup
high fit quality low fit quality
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 21/27

22. A lot of red stains
Measured 40 bloodstains and 35 non-bloodstains
Specificity 100% and sensitivity 98%
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 22/27

23. Case report
stain on paint-can is not blood
(absence of blood was confirmed by tetrabase test)
Reflectance Spectroscopy - Bloodstain Age – Bloodstain recognition 23/27

24. 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
24/27

25. Future research
• Determine influence of environment on ageing
• Extend measurements to dark colored
substrates
• Integrate spectroscopic measurement into
camera system
25/27

26. 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
26/27

27. Acknowledgements
Annemarie Nadort, MSc Nick Laan MSc
Gerda Edelman, MSc Karla de Bruin PhD
Martin van Gemert, PhD
Ton van Leeuwen, PhD
Ted Bijvoets
Rolf Bremmer, MSc Find me on
r.h.bremmer@amc.uva.nl
27/27