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 PhysicsAmsterdam, The Netherlands

Vicky Manti, Saskia van RuthWageningen UR, RIKILT Institute of Food Safety

Wageningen, The Netherlands

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BLOOD EVIDENCE

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Is it blood or ketchup?

Is it human blood?

Who’s blood is it?

Did he get hit by a

hammer?

How old is it?

BLOOD EVIDENCE

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I can test that using chemicals!

I have no idea!

Is it blood or ketchup? How old is

it?

HYPERSPECTRAL IMAGING

Combination of spectroscopy and digital imagingReflectance spectra of each pixelNon-destructive, fast, portableVis NIR wavelength range (400 -1000 nm)

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500 550 600 650 700 750 800-2

-1.5

-1

-0.5

0

0.5

1

1.5

2

Wavelength (nm)R

efle

ctan

ce (

-)

BLOOD STAIN IDENTIFICATIONCan we distinguish blood from other substances?

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In vivo

HEMOGLOBIN

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oxygenation

1 % oxydation

Hb HbO2

Met-Hb

reduction

500 600 700 800

10

20

30

Wavelength (nm)

Abs

orpt

ion

(mm

-1)

HbO2MetHbHC

Ex vivo

HEMOGLOBIN

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-1.5

-1

-0.5

0

0.5

1

1.5

Wavelength (nm)

Cor

r. r

efle

ctan

ce (

-)

1 min1 hour1 day1 week

Hb HbO2

Met-Hb

Hemichrome

oxygenation

oxydation

METHOD

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Specim pushbroom cameraReflectance spectra of:

Blood stainsOther substances (e.g. ketchup, lipstick, wine)

Dark correctionBackground correctionStandard Normal Variate correction

Absorption spectra of HbO2, MetHb and HCMie scatteringLight transport theoryNon linear least squares fit

Measured spectra Theoretical spectra

DATA ANALYSIS

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Blood Non blood

RESULTS

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500 600 700 800

-1

0

1

R2 =0.99827

Wavelength (nm)

Cor

r. r

efle

ctan

ce (

-)

FitBlood

500 600 700 800

-1

0

1

R2 =0.98086

Wavelength (nm)

Cor

r. r

efle

ctan

ce (

-)

FitKetchup

Goodness-of-fit Blood stains were identified

RESULTS

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Blood Non blood

0.7

0.75

0.8

0.85

0.9

0.95

1

Coe

ffic

ient

of

dete

rmin

atio

n (-

)

Sensitivity 100 %Specificity 85 %

BLOOD STAIN AGE ESTIMATIONCan we estimate the time of bleeding?

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AGE ESTIMATION

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500 600 700 800

-1

0

1

Wavelength (nm)

Cor

r. r

efle

ctan

ce (

-)

500 600 700 800

0

-1

1

Wavelength (nm)

Cor

r. r

efle

ctan

ce (

-)

Fresh blood

Old blood

Color change from red to brown, measured quantitativelyRelative contribution of HbO2, MetHb and Hemichrome changes in timeEstimated using least squares fit parameters

0 5 10 15 20 25 300

0.2

0.4

0.6

0.8

1

Age (days)

Rel

ativ

e am

ount

HbO2

MetHbHC

Relative amounts Age estimation

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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.

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The presence of blood of two different ages was proved.

AGE ESTIMATION

NIR SPECTROSCOPYWhat if people wear dark clothing?

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Visible color image

Near infrared image (800 nm)

DARK BACKGROUNDS

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NIR SPECTROSCOPY

Absorbance spectra of coloured cotton

BLOOD STAIN IDENTIFICATIONCan we distinguish blood from other substances?

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METHOD

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FOSS NIR systems 6500 spectrometer

Reflectance spectra of:Blood stains on coloured cottonOther substances (e.g. ketchup, lipstick, wine)

Background correction

Library of 3 blood stains (1 day, 1 week, 1month old)

Compare R2 valuesbetween all blood stains and librarybetween other samples and library.

DATA ANALYSIS

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RESULTS

Blood

Hemoglobin, albumin, globulin

Water

Abs

orba

nce

(a.u

.)

Non blood

RESULTS

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Hemoglobin, albumin, globulin

Water

Abs

orba

nce

(a.u

.)

Sensitivity 100 %Specificity 100 %May reduce when other samples are added to the test set

RESULTS

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BLOOD STAIN AGE ESTIMATIONCan we estimate the time of bleeding?

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AGE ESTIMATION

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Abs

orba

nce

(a.u

.)

RESULTS

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Partial Least Squares RegressionTest set: blood stains on one colorTraining set: blood stains on all other colors

NATIONAL NEWS

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• 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 AaldersSubmitted 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 AaldersSubmitted to Forensic Science International

• Remote spectroscopic identification of blood stainsRolf Bremmer, Gerda Edelman, Tessa Dijn Vegter, Ted Bijvoets, and Maurice AaldersJournal 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 AaldersForensic Science International, 2011

REFERENCES

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