If you regularly watch any police forensics TV shows, then the word "Luminol" is probably already part of your vocabulary. Now, however, you might also want to add the word "Lumicyano." That's the name of a new product that is said to reveal latent fingerprints faster, cheaper and better than other methods.
Along with good ol' fingerprint powder dusting, one process commonly used by crime scene investigators involves exposing touched objects to the fumes given off by a cyanoacrylate compound – known to you and I as super-glue. These fumes react with chemicals in the fingerprint oil (which is mainly sweat residue), polymerizing into a white deposit that causes the print to visually stand out from the surface of the object ... ideally, that is.
Problems can arise if there's not enough visual contrast between the object and the fumed fingerprint, or if the print is simply too insubstantial. In these cases, investigators can employ a second technique, in which a colorant is used that causes the print to fluoresce.
While this approach does make the fingerprint more visible, it also involves taking precautions against the toxic and carcinogenic chemicals required. Additionally, results can take up to two days to obtain, and the process often degrades any DNA present in the fingerprint oil to the point that it can't be read.
That's where Lumicyano comes in. It consists of the usual cyanoacrylate used in standard fuming, combined with an organic compound known as a terazine – terazines being "the smallest fluorescent colorants known to date." Utilizing regular fuming techniques, Lumicyano users are able to instantly obtain fluorescent fingerprints that show up under a UV lamp. Additionally, any DNA in those prints remains unharmed.
Lumicyano was created by a team from the Laboratoire de Photophysique et Photochimie Supramoléculaire et Macromoléculaire, in Paris, working with French company Crime Scene Technology. It has been field tested by police forces in several countries, including Scotland Yard and the FBI.
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