DNA’s identity crisis

Everybody knows that DNA doesn’t lie, right? That’s what CSI has taught us: Just “follow the evidence,” as Gus Grissom says, and you’ll find your perp. Well, what if the statistics we use to convict suspects (those one-in-a-million odds we hear in the courtroom) are off by orders of magnitude? What if some DNA “matches” are nowhere near as airtight as we’ve come to believe? Bicka Barlow, a San Francisco defense attorney, is asking just these questions–and the government is stonewalling her. I explore these questions in “DNA’s Identity Crisis,” a story that took me months to report and write, in the latest issue of San Francisco magazine.

Plus: “Anatomy of a DNA Match: Why finding a criminal through DNA testing is a much dicier process than you’d think.”