AUGUSTA — A man who spent 31 months in prison is free after the district attorney refused to retry him on sexual molestation charges.

For the first time in almost five years, Denny M. Collyer, 37, of Augusta is not facing criminal charges.

He was convicted of two counts of unlawful sexual contact with a child, sent to prison and had his photo and address posted on the state’s online sex offender registry.

Then a judge overturned the sexual molestation convictions, but Collyer faced the prospect of a retrial. On Monday, the district attorney dropped the charges.

“This is life-changing,” Collyer said. “I’ve wanted to get back to the way my life was. I did want an opportunity to go to trial, and they dismissed the charges.”

Collyer’s attorney, Daniel Skolnik, put it succinctly: “He is an unconvicted, unindicted, unaccused free man.”

In June 2006, a jury in Kennebec County Superior Court convicted Collyer of sexual contact between July 1, 2001, and Sept. 12, 2003, with a boy who was 9 and 10 at the time.

In overturning the convictions, the trial judge said Collyer’s trial attorney, Sean Farris, failed to “conduct a reasonable investigation,” including interviewing witnesses.

Farris had been publicly reprimanded by the board that oversees professional conduct of attorneys for mishandling three cases about the same time as Collyer’s trial.

In dismissing the charges, Kennebec County District Attorney Evert Fowle wrote, “After consultation with the victim and the family of the victim, the state believes that, due to the inability to obtain a meaningful sentence after conviction, it would not be in the best interest of the victim . . . to proceed to a second trial.”

Fowle said retrying the case would have put the victim through more trauma, and state law prohibited adding prison time.

“There is little to be gained from going through the same process again,” Fowle said. “As far as we are concerned, 12 people have already rendered their judgment.”

Collyer said the charges forced him to sell an apartment building he owned in Augusta and he lost his home in Fairfield.

“I’ve not held any resentment even though I spent a long time in prison,” Collyer said. “I was a law-abiding guy before. I worked. I paid my taxes. I had a home.”

Skolnik said he was not surprised the charges were dropped.

“The witnesses and evidence that Denny could have and should have presented at the trial clearly would have led to a different result and the prosecution now recognizes that,” he said.

Skolnik said he has prepared a civil complaint on Collyer’s behalf against Farris and members of his firm.

If that goes to trial, Skolnik said, “What we will be doing is carrying the burden to prove Denny’s innocence, and we will do that.”