Serving a life sentence for his role in the Oklahoma City Bombing, Terry Nichols has a lot of time to think and write about the decisions he made.

"It was just so wrong as to what happened," Nichols wrote in April 2010. "There was actually no justification for it. And my heart breaks and grieves daily knowing that I had a part in such a devastating tragedy."

Nichols, 56, is locked up in a small prison cell in Florence, Colo. He has no chance of parole. Several of his letters, published Monday in The Oklahoman newspaper, were written to Jannie Coverdale, who lost two young grandsons in the bombing....