Blogs / Discoblog

Look for this in a future episode of CSI: Detectives expose a piece of paper, a shard of glass, or even a scrap of fabric to a chemical vapor, and within hours, dark brown fingerprints appear. Scientists in the UK report a new method of fingerprint detection that makes fingerprints on almost any material visible to the naked eye. But that’s not all: They say the same method can also read a sealed letter without opening the envelope.

Researcher Paul Kelly stumbled upon the discovery while studying the compound disulfur dinitride. His team first noticed the compound’s fingerprint imaging properties on laboratory glassware. When exposed to vapors of the compound, even in low concentrations, fingerprints left on the glassware would stain a dark brown. Residues from the fingerprints were causing disulfur dinitride to form a dark brown polymer.

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Murderers desperate to get rid of evidence might want to consider using bleach to wash away stains. But not just any bleach will do. When old-school chlorine-based bleach is splashed all over blood-stained clothing, even if the clothes are washed ten times, DNA is still detected.

So for the criminal aspiring for perfection, here’s the secret you’ll need to know: It’s the oxygen-producing detergents that will get rid of any incriminating evidence for good.

Researchers at the University of Valencia tested oxygen bleach on blood-stained clothing for two hours and found that it destroys all DNA evidence. Forensic tests such as luminal tests rely on the ability of blood to uptake oxygen: A protein in the blood called hemoglobin (responsible for transporting oxygen throughout the body) reacts with hydrogen peroxide and gives a positive test result.

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