WARREN – The teenage lover who murdered Pamela Smart’s husband 17 years ago is asking a judge to reduce his 28-year prison sentence.

William Flynn was a 16-year-old high school student in May 1990 when, at Pamela Smart’s urging, he fatally shot Gregory Smart at the couple’s Derry, N.H., condominium. Flynn was having an affair with Pamela Smart, a 22-year-old media coordinator at his school.

In a handwritten letter to a Superior Court judge in Brentwood, N.H., Flynn, now 33, says he waited to ask for a sentence reduction until he had spent as many years behind bars as he had free.

“I have never asked for one until now, because as terrible of a place as prison is, I know I deserved to be here,” he wrote.

Flynn says he continues to bear the guilt of his actions and knows he can’t make up for what he has done.

“I hoped that perhaps one day, if I helped enough people and righted enough wrongs, that I would be worthy of forgiveness,” he wrote. “I have understood for many years now that my debt is perpetual and I will be paying for it my entire life.

“One cannot overwhelm a sin with good deeds – you must make amends for the sin,” he writes. “But how do you make amends for taking a life? You can’t.”

Flynn married while in prison and has a stepdaughter.

The letter is accompanied by statements of support from friends, corrections officials and people who work with Flynn at the Maine State Prison in Warren.

“He conducts himself quietly, honorably and with a humble, helpful grace,” wrote corrections officer Nova Hirsch. “He is a breath of fresh air that whips through the awful stagnation here.”

The documents also note that Flynn earned his high school equivalency diploma in prison, organizes donations from inmates to charities such as Toys for Tots, has learned to play several musical instruments, and performs at prison concerts and meetings of a Christian prisoners’ group.

Flynn also works behind bars as a paid electrician’s assistant, where he is allowed to work on alarm systems and closed-circuit cameras, according to the documents.

The electrician who works with Flynn praised his assistant in a letter. The electrician wrote that he is “looking forward to introducing him to potential employers, my friends and my family.”

Flynn was sentenced in 1992 to a 40-year-to-life sentence for second-degree murder with 12 years suspended. He is not eligible for parole until 2018. No hearing has been scheduled on his request.

Flynn’s friend Patrick Randall, who held Gregory Smart down during the shooting, pleaded guilty to being an accomplice to second-degree murder. He is at the same prison and cannot apply for parole until 2018.

Vance Lattime, a friend who drove the getaway car, got 18 years to life and won release from prison in May 2005. Another teen accomplice, Raymond Fowler, who waited in the car with Lattime, also has been released from prison.