Forensic nightmare: 'Touch DNA'
Heard of “touch DNA?” This mundane yet menacing phenomenon exposes the double-edged sword of forensic science. With just an innocent handshake, an indirect transfer of epithelial cells, you could find yourself suspected of heinous crimes.
This year, I'll be using my syndicated column and new investigative show on CRTV.com to shed light on touch DNA's use and abuse in the criminal justice system. Detection methods involving tinier and tinier DNA samples have advanced rapidly. But DNA's mere presence does not prove a crime happened or tell how or when the material got to its discovered location.
Contrary to Hollywood, DNA is not a synonym for “guilty.”
In a few high-profile cases, touch DNA led investigators astray. Trace amounts of DNA in 2007 were key to American student Amanda Knox's murder conviction in Italy. But when an American forensic expert and others exposed problems with the DNA evidence, the Italian Supreme Court threw out her conviction eight years after the killing.
At the annual American Academy of Forensic Sciences conference last February, experts spotlighted the case of a homeless man charged with murdering a Silicon Valley mogul at his mansion — despite the accused being hospitalized and nearly comatose the night the crime occurred in 2012. As Scientific American reported, the defendant's DNA had been transferred inadvertently by paramedics who had treated him three hours before arriving at the businessman's home. They used the same oxygen monitor on both men's fingers. The case is a definitive example of “a DNA transfer implicating an innocent person,” the journal noted.
Thanks to joint reporting by Denver's 9News and the Boulder Daily Camera, the Boulder County district attorney is reopening the DNA portion of the JonBenet Ramsey murder investigation. Exonerating the Ramsey family in 2008, his predecessor concluded that an unknown male's DNA on JonBenet's underwear must be the killer's because no innocent explanation existed for it. A growing body of peer-reviewed scientific literature says otherwise. Unfortunately, many state crime labs and police departments haven't caught up.
In my own investigation of the sexual-assaults case of former Oklahoma City policeman Daniel Holtzclaw, who was sentenced to 263 years in prison, I've encountered alarming ignorance of DNA evidence's pitfalls and limitations, compounded by the stubborn unwillingness of ill-informed detectives and prosecutors to acknowledge their scientific shortcomings. In 2014, Holtzclaw was convicted despite a mountain of reasonable doubt.
As Erica Fuchs, a micro- and molecular biologist with a lab research specialty in DNA who supports Holtzclaw and has made crucial discoveries involving the DNA evidence, told me: “When people invest themselves in a belief, it can be easier to ignore evidence that conflicts or challenges that belief. Admitting that non-intimate skin cell DNA transfer is a reasonable explanation for the DNA evidence in Daniel's case may make a lot of people in the media question their assumptions and actions.”
Michelle Malkin is host of “Michelle Malkin Investigates” on CRTV.com.