FARMINGTON — A judge sentenced a former Chesterville man Wednesday to 15 years in prison for sexually assaulting three brothers from January 2012 and March 2014.

The incidents occurred in Chesterville, Farmington and Wilton when the boys were under the age of 14, Assistant District Attorney Claire Andrews said.

Jonathan M. Clark, 29, who lives in Lovell, pleaded guilty to 10 felony counts of gross sexual assault in Franklin County Superior Court. The state dismissed 19 sexual assault charges and seven other sex-related crimes as part of a plea agreement.

Justice Susan Oram sentenced Clark to 15 years on each charge, with the sentences to be served concurrently. He will have 30 years of supervised release after serving the sentence.

Gross sexual assault is punishable by up to 50 years in prison and a $50,000 fine.

Clark had been held on $200,000 cash bail since his arrest by Maine State Police in April 2014.

If the case had gone to trial, Andrews said the court would have heard testimony from State Police Detective Herbert Leighton that he and Detective Ethel Ross interviewed Clark at the Franklin County jail and Clark admitted to engaging in sex acts dozens of times with the boys over two years.

A Maine Department of Health and Human Services representative and a representative of The Children’s Advocacy Center interviewed the boys separately, according to the affidavit.

Amid heavy security in the courtroom Wednesday, the boys’ mother described Clark as “heartless” and said, “He sexually assaulted my three boys and threatened their lives. He has made me feel like a failure because I failed to protect them.”

She said her sons are scared and one of them won’t talk to her because she failed to protect him.

The boys will only feel secure if they know Clark is in prison, she said. He needs to be locked up in a cage, she said.

“Jonathan Clark is not safe. He is not safe for our community,” she said.

She asked the court to give Clark the maximum sentence.

A caseworker for one of the boys said he is going through trauma-related issues and distrusts authority.

The boys’ stepfather asked the court to throw away the plea agreement and give Clark the maximum sentence.

“Fifteen years is a slap in the face to the children of this state,” he said.

At the direction of his attorney, Brad Grant, Clark looked straight ahead at the judge and said, “I would like to apologize to the victims and family and (for) everything I have done to hurt them and everybody else. I’m truthfully sorry.”

“Damage has been done to some of the most vulnerable people in the community,” Oram said.

She said mitigating factors include Clark having no criminal record, taking responsibility for his actions and not making the boys face the trauma of a trial. She also took into account the ages of the boys, she said.

Clark will be under Department of Corrections supervision for the next 45 years, she said. This and other conditions, including no contact with the boys or any children under age 16, periodic judicial review and registering as a lifetime sex offender, will provide necessary protection to the community, she said.

dperry@sunjournal.com