DNA evidence has become the gold standard for criminal investigations, but researchers in Israel say that finding DNA at a crime scene may not be evidence of a crime, but rather the handiwork of a clever biology student.
In a paper published in Forensic Science International, Dan Frumkin, a private forensics researcher, claims that fabricating DNA evidence has become so easy that "[a]ny biology undergraduate could perform this."
Frumkin outlines two methods for fabricating DNA evidence. The first requires access to a small sample of an individual's DNA, such as a hair or a bit of saliva. The size of the sample is then increased through a common technique known as DNA amplification. Then the hopeful framer takes blood from a different individual, centrifuges it to remove the DNA-carrying white blood cells, and leaves only the red blood cells, which contain no DNA. The person then adds the amplified DNA to the blood sample, creating a handy supply of blood that could be splashed onto a crime scene to implicate the chosen target.
The second method requires no actual sample of DNA, but a person's DNA profile, which may be stored in a law enforcement database. These profiles identify variations at 13 specific spots in an individual's genome. Frumkin claims that a scientist could keep a library of a cloned snippets of DNA representing the variants at the 13 spots (he estimates 425 samples would be needed in all), and he or she could mix the snippets to create a DNA sample matching anyone's genetic profile.
Frumkin says that, at the moment, there are ways to determine whether DNA evidence has been fabricated (and his own company, Nucleix, provides such tests), but it's a step forensic labs don't normally take. Although some respondents question whether criminals will actually use these techniques to throw suspicion off themselves and onto others, Tania Simoncelli, an American Civil Liberties Union science adviser, suggests that it's time for courts to reevaluate the reliability of DNA evidence:
"DNA is a lot easier to plant at a crime scene than fingerprints," she said. "We're creating a criminal justice system that is increasingly relying on this technology."