Forensics gone wrong: When DNA snares the innocent

On a Tuesday morning in Boise, biologist Greg Hampikian is on speakerphone with Christopher Tapp, an inmate at the Idaho State Correctional Institution. Tapp is in prison for a murder he swears he did not commit. Many others think he’s innocent as well—lawyers, journalists, an organization of former judges; even the victim’s mother. No one has fought for him longer than Hampikian, a researcher at Boise State University (BSU). “How’re you doing, Chris?” Hampikian begins. “I’m having a good time at summer camp,” Tapp says gamely. “Although you know me … I’m in the hole again”—solitary. “There was a mutual misunderstanding between me and someone else.” He mentions that he and his wife are getting divorced.

“I’m really sorry Chris, that’s a lot to deal with,”  Hampikian says. “You know my offer still stands. I’ll pay tuition for any courses you want to take.” A pause. “You know we got a decision from the court to move forward with a new DNA test. But the court is only allowing us a limited amount and we have to decide which test is...