Damien Echols Appears on CBS SUNDAY MORNING Today, 9/16

Damien Echols spent 18 years in jail for a crime he says he didn't commit. However, life on the outside isn't as easy as most would expect. Echols, who along with two others was convicted for the murders of three boys, tells CBS SUNDAY MORNING WITH Charles Osgood he lives in fear.

"I can't even describe what the fear is or where it comes from," Echols tells 48 HOURS MYSTERY correspondent Erin Moriarty in an interview airing this weekend on CBS SUNDAY MORNING. "It's just like this free-floating anxiety. It's what – literally my life has become – is that I've been injected into this whole new world. And I'm having to learn everything."

In August 2011, Echols and two other men were released as part of an unusual plea deal after spending nearly two decades in Arkansas prisons. Echols, Jason Baldwin and Jesse Misskelley are known as the West Memphis 3, and in 1993 were teenagers living in West Memphis, Ark., when they were arrested and convicted of murdering three boys.

"You never go into a deep sleep," he says of his life in jail. "You always have to be ready for the next person that's going to try to hurt you."

There was no physical evidence connecting Echols or the others to the murders and over the years, considerable information surfaced supporting their innocence. It was attention from 48 HOURS MYSTERY and another documentary that helped draw attention to the case of the three men. The men were released after they pled guilty to the murders.

"It was a deal with the devil, but it was a deal I really didn't have a choice to take if I wanted to live," Echols tells Moriarty. "My health was going fast. I was dying in there. I knew if I didn't take that deal, I was never going to live to see outside those walls."

Moriarty talks with Damien Echols and his wife Lorri, whom he met and married in prison, about his stay in jail, life after being released, and his new book, Life after Death.

Moriarty's full interview with Echols will air today, Sept. 16 on CBS SUNDAY MORNING (9:00-10:30 AM, ET) on the CBS Television Network. Rand Morrison is the executive producer.