OMG! There's Cocaine on Everything!

A new forensic test devised by a British student can detect extremely tiny traces of cocaine — and will probably further corroborate what we already knew: cocaine is everywhere. But are ultra-sensitive lab tests helping us find evidence or making that evidence harder to decipher?

Sonica Devi, a 22-year-old Derby University student, found a method that can detect cocaine down to one trillionth of a gram. When she tested it out on pay phones in London, she found coke on one in six coin slots. Her discovery adds more ammunition to a story that's been floating around for years — that four out of five American dollar bills has traces of cocaine. (Which is true, by the way — once one bill is used to snort cocaine, the powder floats like dust through ATMs, cash drawers and counting machines).

These discoveries should do more than create an OMG! headline for irresponsible, sensationalist bloggers (like, um, me). The ubiquitous presence and rapidly advancing technology should remind us that criminal cases shouldn't simply turn on what a forensic test finds — it takes experts to interpret the evidence, and a critical eye from jurors and attorneys to determine what the evidence proves.

For example: if I'm suspected of dealing cocaine, and a police lab finds coke on bills in my wallet, I'd better hope that my attorney points to the evidence that cocaine is in plenty of innocent wallets. This holds true for all forms of forensics: the real world isn't like CSI, and it takes a critical eye to determine exactly what a shiny forensic test actually shows.

Blood on a carpet? Without DNA analysis, it could be from anything.

Fibers matching a perpetrator's clothes found in a store after a robbery? How rare are the fibers? How clean was the store?

An employment drug test finds marijuana in a person's system. Does that mean they're a pothead or simply that they went to a party three weeks ago? (Don't even get me started on this one...)

Rapid advances in forensic science and public fascination with shows like CSI create a dangerous situation in the courtroom. That's why both defense attorneys and prosecutors complain about the so-called "CSI Effect." Prosecutors say it's hard to get a conviction without forensics (and many crimes simply don't lend themselves to forensics). Meanwhile, defense attorneys say that anytime the prosecution trots out a scientist — to testify about traces of cocaine in a wallet, for example — the jury automatically assumes that what such a person's saying is true.

For these reasons, the U.S. Supreme Court's decision last year in Melendez-Diaz v. Massachusetts is a critical one. The justices found that defendants have a constitutional right to cross-examine lab analysts who conduct forensic tests in their case. Paperwork reporting a positive result for drugs or blood can be misleading, and it takes a defense lawyer's questioning of an expert to get to the true meaning of the evidence in some cases.

Most of us are safe from being accused of drug possession, thanks to Devi's new test. But just in case, you might want to wash that coke off your hands.

Photo Credit: In a NY State of Mind