Blood Camera to Spot Invisible Stains at Crime Scenes [Cameras]

Call it CSI: Abracadabra. A camera that could make invisible substances reappear as if by magic could allow forensics teams to quickly scan a criminal offense scene for blood stains without tampering with valuable evidence.

The prototype camera, developed by Stephen Morgan , Michael Myrick and co-workers at the University of South Carolina in Columbia, can detect blood stains even when the sample has been diluted to at least one part per 100.

At present, blood stains are detected using the chemical luminol, that is sprayed around the crime scene and reacts with the iron in any blood present to emit a blue glow which might be seen in the dead of night. However, luminol is toxic, can dilute blood samples to a level at which DNA is hard to recover, and may smear blood spatter patterns that forensic experts use to aid determine how the victim died. Luminol can even react with substances like bleach, rust, fizzy drink and occasional, causing it to supply false positives.

The camera, by contrast, can distinguish between blood and all four of these substances, and may well be used to spot stains that require further chemical analysis without interfering with the sample.

To take an image of a scene, the camera beams pulses of infrared light onto a surface and detects the infrared it really is reflected go into reverse it. A transparent, 8-micrometre-thick layer of the protein albumin placed in front of the detector acts as a filter, making a dilute blood stain occur against its surroundings by filtering out wavelengths that aren’t characteristic of blood proteins.

By modifying the chemical used for the filter, it would be possible to detect contrasts between a surface and any form of stain, says Morgan. ” With the proper filter, it’ll be possible to detect [sweat and lipids] in fingerprints which might be not visible to the naked eye,” he says. ” Inside the same way that you can also detect drugs on a surface, or trace explosives.”

Journal reference: Analytical Chemistry, DOI: 10.1021/ac101107v

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This post is tagged: blood spatter patterns, criminal offense, forensic experts, journal reference, university of south carolina, university of south carolina in columbia