A breakthrough invention by Stephen Morgan, Michael Myrick at the University of South Carolina, Columbia who have developed a camera that could now allow forensics experts to find blood stains from a crime scene quickly and that too without tampering with valuable evidence. The camera can detect the blood stains even if special care has been taken to destruct evidence by washing the crime area 100 times.

At present, a chemical luminol is used to find blood stains. The chemical is sprayed around the crime scene and the reaction starts because of the presence of iron in blood. It emits a blue glow. However, luminol is toxic and can dilute blood to an extent that it becomes difficult to find the DNA. Also it reacts with substances like bleach, rust, fizzy drink and coffee, often giving misleading positive results.

The camera on the other hand can distinguish between blood and all four mentioned substances. The best part is it can spot the satins without interfering with the samples which is very crucial for further chemical analysis.

So how does the camera work? It takes an image by putting a beam of infrared light onto a surface and detects the infrared that is reflected back. Then, a transparent, 8-micrometre-thick layer of the protein albumin is placed in front of the detector that acts as a filter. This process dilutes blood stain and shows up against its surroundings by filtering out wavelengths that aren't characteristic of blood proteins.

"With the appropriate filter, it should be possible to detect sweat and lipids in fingerprints that are not visible to the naked eye," said Morgan. "In the same way you could also detect drugs on a surface, or trace explosives."