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 4/6/2015 WSC-08 1 BLOOD EVIDENCE Is it human blood? Who’s blood is it? Did he get hit by a hammer? Is it blood or ketchup? 4/6/2015 How old is it? WSC-08 2 BLOOD EVIDENCE I can test that using chemicals! I have no idea! Is it blood or ketchup? 4/6/2015 How old is it? WSC-08 3 HYPERSPECTRAL IMAGING Combination of spectroscopy and digital imaging Reflectance spectra of each pixel Non-destructive, fast, portable Vis NIR wavelength range (400 -1000 nm) 2 Reflectance (-) 1.5 1 0.5 0 -0.5 -1 -1.5 -2 500 550 600 650 700 750 800 Wavelength (nm) 4/6/2015 WSC-08 4 Can we distinguish blood from other substances? BLOOD STAIN IDENTIFICATION 4/6/2015 WSC-08 5 HEMOGLOBIN In vivo oxygenation Hb HbO2 1 % oxydation Met-Hb 4/6/2015 WSC-08 6 HEMOGLOBIN Ex vivo oxygenation Hb HbO2 MetHb HC -1 Absorption (mm ) 30 HbO2 oxydation Met-Hb 20 10 500 600 700 800 Wavelength (nm) 1.5 Hemichrome Corr. reflectance (-) 1 0.5 0 -0.5 -1 1 min 1 hour 1 day 1 week -1.5 4/6/2015 WSC-08 -2 500 550 600 650 700 Wavelength (nm) 750 800 7 METHOD Specim pushbroom camera Reflectance spectra of: Blood stains Other substances (e.g. ketchup, lipstick, wine) 4/6/2015 WSC-08 8 DATA ANALYSIS Measured spectra Theoretical spectra Dark correction Background correction Standard Normal Variate correction 4/6/2015 Absorption spectra of HbO2, MetHb and HC Mie scattering Light transport theory Non linear least squares fit WSC-08 9 RESULTS Non blood Fit Blood Corr. reflectance (-) Corr. reflectance (-) Blood 1 0 -1 R2 = 0.99827 500 600 700 Fit Ketchup 1 0 -1 800 500 Wavelength (nm) 4/6/2015 R2 = 0.98086 600 700 800 Wavelength (nm) WSC-08 10 RESULTS Goodness-of-fit Blood stains were identified Sensitivity 100 % Specificity 85 % 1 Coefficient of determination (-) 0.95 0.9 0.85 0.8 0.75 0.7 Blood 4/6/2015 Non blood WSC-08 11 Can we estimate the time of bleeding? BLOOD STAIN AGE ESTIMATION 4/6/2015 WSC-08 12 AGE ESTIMATION Corr. reflectance (-) Color change from red to brown, measured quantitatively Relative contribution of HbO2, MetHb and Hemichrome changes in time Estimated using least squares fit parameters Fresh blood 1 0 -1 500 600 700 800 Corr. reflectance (-) Wavelength (nm) Old blood 1 0 -1 500 600 700 800 Wavelength (nm) 4/6/2015 WSC-08 13 AGE ESTIMATION Relative amounts Age estimation 1 HbO2 MetHb HC Relative amount 0.8 Ages of blood stains up to 2 years old were estimated. Accuracy decreases with age. Important NEW information about temporal aspects of crime. 0.6 0.4 0.2 0 0 4/6/2015 5 10 15 20 Age (days) 25 30 WSC-08 14 AGE ESTIMATION The presence of blood of two different ages was proved. 4/6/2015 WSC-08 15 What if people wear dark clothing? NIR SPECTROSCOPY 4/6/2015 WSC-08 16 DARK BACKGROUNDS Visible color image 4/6/2015 Near infrared image (800 nm) WSC-08 17 NIR SPECTROSCOPY Absorbance spectra of coloured cotton 4/6/2015 WSC-08 18 Can we distinguish blood from other substances? BLOOD STAIN IDENTIFICATION 4/6/2015 WSC-08 19 METHOD FOSS NIR systems 6500 spectrometer Reflectance spectra of: Blood stains on coloured cotton Other substances (e.g. ketchup, lipstick, wine) 4/6/2015 WSC-08 20 DATA ANALYSIS 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. 4/6/2015 WSC-08 21 RESULTS Blood Hemoglobin, albumin, globulin Absorbance (a.u.) Water 4/6/2015 WSC-08 22 RESULTS Hemoglobin, albumin, globulin Non blood Absorbance (a.u.) Water 4/6/2015 WSC-08 23 RESULTS Sensitivity 100 % Specificity 100 % May reduce when other samples are added to the test set 4/6/2015 WSC-08 24 Can we estimate the time of bleeding? BLOOD STAIN AGE ESTIMATION 4/6/2015 WSC-08 25 Absorbance (a.u.) AGE ESTIMATION 4/6/2015 WSC-08 26 RESULTS Partial Least Squares Regression Test set: blood stains on one color Training set: blood stains on all other colors 4/6/2015 WSC-08 27 NATIONAL NEWS 4/6/2015 WSC-08 28 4/6/2015 WSC-08 29 REFERENCES • 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 4/6/2015 WSC-08 30