'Zoloft Defense' Killer Speaks

Sixteen-year old Christopher Pittman is only a few months into serving a thirty-year jail sentence for the brutal murder of his grandparents, Joe and Joy Pittman, in 2001 -- a crime he blamed on the popular antidepressant, Zoloft.

48 Hours Correspondent Erin Moriarty, who's been following the case from the beginning, sat down with Pittman for an exclusive interview.

She says, despite the guilty verdict, it was anything but an open and shut case.

The February trial captured national attention because of the unique defense Pittman used.

He was only 12 and on the prescription drug Zoloft when he killed his grand parents, and defense attorneys argued it was the medication that triggered his violent behavior.

But it's clear that the prosecutor, Barney Giese, believes this was a case of murder, pure and simple. "This is as vicious a case as you're gonna see. Vicious," he told Moriarty.

The case, argues Giese, has nothing to do with the medication Pittman was taking: "I don't think that Zoloft, to be honest, had any effect on him. I really don't. Our law is very specific: Did you know the difference between right and wrong?"

The defense, led by Texas lawyer Andy Vickery, says it has everything to do with Zoloft.

"The theory of our case is that a powerful, mind-altering drug was given to a kid that shouldn't have got it in the first place," Vickery points out. "And it triggered very violent behavior."

Vickery stands by the decision not to have Pittman take the stand: "Would you put your 15-year-old on the stand to be grilled by a seasoned prosecutor? C'mon -- he's 15 years old."

But in an exclusive interview with Moriarty -- shortly before his case went to the jury – Pittman had plenty to say.