WARREN — Dennis Dechaine, one of the most notorious prisoners in Maine history, has maintained the same theme in the handful of interviews he has done with various newspapers and television stations since his conviction in 1989.

He claims he did not murder 12-year-old Sarah Cherry.

During an hour-long interview at the prison on March 22, Dechaine firmly stood behind that assertion, and he said he wanted the public to hear once again his thoughts about the case because his motion for a new trial is expected to be heard later this year.

It was his first interview with The Portland Press Herald/Maine Sunday Telegram in 18 years.

“I grew up believing that the justice system was sacrosanct,” Dechaine said. “I grew up believing that it wasn’t flawed. Well, I’m here to tell you that it does make mistakes, and not just to Dennis Dechaine.”

No longer the wiry 30-year-old farmer who was arrested on July 8, 1988, Dechaine carries more weight now and has the appearance of an average middle-aged man, with wrinkles at the corners of his eyes.

But he’s not average, as the prison shirt with the number 1725 stitched above his breast pocket indicates. Dechaine is the man at the center of the case that has been disputed in Maine’s court system longer than any other.

On the day of the interview, Dechaine walked into a visitation room wearing prison-issued blue jeans and a neatly pressed blue shirt. A security gate slammed shut behind him.

Dechaine described his life in prison as “an exercise in structured monotony.”

He works each day as a clerk in the Maine State Prison’s upholstery shop, eats lunch with other inmates, goes back to work and then eats supper.

There are 55 other men who share the living unit, known as a pod. Dechaine has developed friendships with many of them, some of whom are also serving lengthy prison terms. Dechaine was sentenced to life, meaning he will remain at the facility until he dies, barring any radical change in his case.

After supper, Dechaine has about two hours of free time before lockdown at 9 p.m.

Sometimes he reads, or watches television with other inmates. “The Keep” by Jennifer Egan was one of the books he read this spring.

He can also use the phone, but it’s pricey at 30 cents a minute, Dechaine said. He writes several letters a week to relatives and friends.

He also has studied French throughout his incarceration, and he has taught the language to several inmates.

If Dechaine ever got out of prison, he said he would take up agriculture, horticulture or a combination of both.

He said, “I miss farming in a way that a non-farmer couldn’t possibly understand. Some of the greatest excitement I’ve had recently was talking to a fellow prisoner about retrofitting an Allis-Chalmers G engine with a diesel engine.”

His former wife, Nancy Emmons, supported him at the trial and said she did not believe Dechaine was guilty, but they divorced shortly after the trial. Emmons moved out of state and remarried. She and Dennis had no children, and they do not keep in touch.

Brothers Philip and Don Dechaine, who live in far northern Maine, have been able to visit Dennis at least a few times each year. A fourth brother, Francis, lives in Washington state and has not seen Dennis as much as the others.

“The fantasy of being free rarely goes beyond just being with my family,” he said. “I’d be so satisfied with that for so long. That is what I think about most.”