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Identification and age estimation of blood stains

Identification and age estimation of blood stains. Gerda Edelman ( G.J.Edelman@amc.nl ) Maurice Aalders, Ton van Leeuwen Academic Medical Center, Biomedical Engineering and Physics Amsterdam, The Netherlands Vicky Manti, Saskia van Ruth Wageningen UR, RIKILT Institute of Food Safety

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Identification and age estimation of blood stains

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  1. Identification and age estimation of blood stains Gerda Edelman (G.J.Edelman@amc.nl) Maurice Aalders, Ton van Leeuwen Academic Medical Center, Biomedical Engineering and Physics Amsterdam, The Netherlands Vicky Manti, Saskia van Ruth Wageningen UR, RIKILT Institute of Food Safety Wageningen, The Netherlands WSC-08

  2. Who’s blood is it? Is it human blood? Blood evidence Did he get hit by a hammer? Is it blood or ketchup? How old is it? WSC-08

  3. I can test that using chemicals! I have no idea! Blood evidence Is it blood or ketchup? How old is it? WSC-08

  4. Combination of spectroscopy and digital imaging Reflectance spectra of each pixel Non-destructive, fast, portable Vis NIR wavelength range (400 -1000 nm) • hyperSpectral imaging WSC-08

  5. Can we distinguish blood from other substances? Blood stain identification WSC-08

  6. oxygenation Hb HbO2 • In vivo Hemoglobin 1 % oxydation reduction Met-Hb WSC-08

  7. oxygenation Hb HbO2 • Ex vivo Hemoglobin oxydation Met-Hb Hemichrome WSC-08

  8. Specim pushbroom camera • Reflectance spectra of: • Blood stains • Other substances (e.g. ketchup, lipstick, wine) Method WSC-08

  9. Dark correction • Background correction • Standard Normal Variate correction • Absorption spectra of HbO2, MetHb and HC • Mie scattering • Light transport theory • Non linear least squares fit • Measured spectra • Theoretical spectra Data analysis WSC-08

  10. Blood • Non blood • Results WSC-08

  11. Sensitivity 100 % • Specificity 85 % • Goodness-of-fit • Blood stains were identified Results WSC-08

  12. Can we estimate the time of bleeding? Blood stain Age estimation WSC-08

  13. Color change from red to brown, measured quantitatively • Relative contribution of HbO2, MetHb and Hemichrome changes in time • Estimated using least squares fit parameters • Age estimation WSC-08

  14. Age estimation • Relative amounts • Age estimation • Ages of blood stains up to 2 years old were estimated. • Accuracy decreases with age. • Important NEW information about temporal aspects of crime. WSC-08

  15. The presence of blood of two different ages was proved. • Age estimation WSC-08

  16. What if people wear dark clothing? NIR spectroscopy WSC-08

  17. Visible color image • Near infrared image (800 nm) • Dark backgrounds WSC-08

  18. Absorbancespectra of coloured cotton • Nir spectroscopy WSC-08

  19. Can we distinguish blood from other substances? Blood stain identification WSC-08

  20. FOSS NIR systems 6500 spectrometer • Reflectancespectra of: • Blood stains on coloured cotton • Other substances (e.g. ketchup, lipstick, wine) Method WSC-08

  21. Background correction • Library of 3 blood stains (1 day, 1 week, 1month old) • Compare R2 values • between all blood stains and library • between other samples and library. Data analysis WSC-08

  22. Results Hemoglobin, albumin, globulin Blood Water Absorbance (a.u.) WSC-08

  23. Hemoglobin, albumin, globulin Water • Non blood Results Absorbance (a.u.) WSC-08

  24. Sensitivity 100 % • Specificity 100 % • May reduce when other samples are added to the test set Results WSC-08

  25. Can we estimate the time of bleeding? Blood stain Age estimation WSC-08

  26. Age estimation Absorbance (a.u.) WSC-08

  27. Partial Least Squares Regression • Test set: blood stains on one color • Training set: blood stains on all other colors Results WSC-08

  28. National news WSC-08

  29. WSC-08

  30. Identification and age estimation of blood stains on coloured backgrounds by near infrared spectroscopy Gerda Edelman, Vicky Manti, Saskia M. van Ruth, Ton van Leeuwen, Maurice Aalders Submitted to Forensic Science International • Hyperspectral imaging of the crime scene for the automatic detection and identification of blood stains Gerda Edelman, Ton van Leeuwen, Maurice Aalders Submitted to Forensic Science International • Remote spectroscopic identification of blood stains Rolf Bremmer, Gerda Edelman, Tessa Dijn Vegter, Ted Bijvoets, and Maurice Aalders Journal of Forensic Sciences, 2011 • Age estimation of blood stains by hemoglobin derivative determination using reflectance spectroscopy Rolf Bremmer, Annemarie Nadort, Martin van Gemert, Ton van Leeuwen, Maurice Aalders Forensic Science International, 2011 • References WSC-08

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