The difficulty now is in identifying and addressing the remaining cases quickly and thoroughly. Most of the convictions are decades old; witnesses, memories, and even evidence may be long gone.
And courts have only made the problem worse by purporting to be scientifically literate, and allowing in all kinds of evidence that would not make it within shouting distance of a peer-reviewed journal. Of the 329 exonerations based on DNA testing since 1989, more than one-quarter involved convictions based on “pattern” evidence — like hair samples, ballistics, tire tracks, and bite marks — testified to by so-called experts.
While the F.B.I. is finally treating this fiasco with the seriousness it deserves, that offers little comfort to the men and women who have spent decades behind bars based on junk science.