When the California law, Proposition 69, passed, it was widely believed that the innocent had nothing to fear from having their genetic profiles in a database, said
UC Irvine criminology professor William Thompson, considered the U.S. leading authority on DNA laboratory error.
Now, he said, "when you look at all the errors that have come to light around the world -- and we're only finding the tip of the iceberg -- it really raises concerns about how many people you want to have in a database. There are certainly doubts in my mind whether I would want to be in one."
The records show, for instance, that between 2003 and 2007, the Santa Clara County district attorney's crime laboratory caught 14 instances in which evidence samples were contaminated with staff members' DNA, three in which samples were contaminated by an unknown person and six in which DNA from one case contaminated samples from another.
The records also revealed three instances in which DNA samples were accidentally switched, one in which analysts reported incorrect results and three mistakes in computing the statistics used in court to describe the rarity of a DNA profile.
