Nashville, N.C. — After five years in prison, Mike Peterson's story hasn't changed.

Peterson, who was convicted of killing his wife, Kathleen Peterson, in their upscale Durham home in December 2001, continues to maintain his innocence.

"I was devastated. I still am. I have these wonderful pictures of Kathleen in my cell. I look at them every day," Peterson said Friday in an interview from Nash Correctional Institution, where he is serving a life sentence.

Kathleen Peterson was found dead in a pool of blood at the bottom of a staircase in the couple’s Forest Hills mansion. Mike Peterson has maintained for years that his wife died in an accidental fall, but he said Friday that he's not sure how she died.

"That is the only thing I can't answer you honestly because I don't know," he said.

Since Peterson's conviction in October 2003, various theories have been floated about his wife's death. The latest came last fall when an attorney argued that a tire iron found in Peterson's neighborhood was never disclosed to the defense, which should entitle him to a new trial.

"Five years later we find, 'Wait a minute, you were looking for a tire iron? You discover a tire iron? You tested the tire iron? You didn't tell us anything about that?'" he said. "Was the tire iron (important)? I don't know. I have no idea. But is that information that would have changed the defense? I think so."

Prosecutors said the tire iron had nothing to do with the case, and a judge denied the motion.

Peterson said his greatest regret was not testifying in his own defense during the murder trial, especially when sordid details of his personal life, including his propositioning a male escort, were allowed into evidence.

"What sells, the trashy novel or the medical textbook? Of course, it was the trashy novel," he said. "In retrospect, I should have talked and (explained) all these things. Everybody should have talked."

Peterson, who still wears his wedding ring, said he spends his days in prison reading, writing, exercising and working as a janitor. "Time stopped for me that day that she died," he said."

He said he hopes to publish a book about prison life and said he won't give up the fight for his freedom.

"We each create our own heaven and hell," he said. "It's pretty hard to make a heaven out of this place, but I guarantee it's not going to be a hell. I'm going to do the best I possibly can in here, and I think I've done pretty well."