AUBURN — A Sabattus man pleaded guilty Friday to nearly a dozen counts of gross sexual assault against a preteen and agreed to serve 15 years in prison.

Michael Gagnier, 34, of 20 High St., pleaded guilty in Androscoggin County Superior Court to 10 counts of the Class A crime, each punishable by up to 30 years in prison. He also pleaded guilty to a charge of tampering with a victim, a Class B felony, punishable by up to 10 years in prison.

An Androscoggin County grand jury indicted Gagnier in June on 38 counts of gross sexual assault. Most of those charges will be dismissed.

Justice MaryGay Kennedy accepted Gagnier’s plea to a sentence of 25 years in prison with 10 years suspended, meaning he is expected to serve 15 years. When he is released from prison, he will be on probation for 18 years. He also must register as a sex offender for the rest of his life.

Assistant District Attorney Lisa Bogue said Friday the victim was 10 years old when she was first assaulted and 13 when the final assault occurred.

In 2012, the victim revealed Gagnier’s actions to a friend at school, who passed along the information to a guidance counselor. The crimes came to light last year after the girl told a friend who told a youth worker at a Lewiston church retreat about the repeated assaults.

Gagnier and his wife used force, intimidation or bribes in an attempt to convince the victim to withhold evidence, according to the indictment.

A Sabattus police officer said Gagnier admitted having sex with the girl over a three-year period, confirming the victim’s allegations. He said he was using pills at that time.

A sentencing date hasn’t been set.

Gagnier has no prior criminal record.

Michael Gagnier was arrested and charged nearly a year ago; his wife, Christal, was arrested in June on a sealed warrant after an indictment by a grand jury on three counts related to her husband’s criminal activities.

Christal Gagnier, 26, was charged with one count of tampering with a victim and aggravated unlawful furnishing of scheduled drugs, a Class C felony punishable by up to five years in prison. She also was charged with endangering the welfare of a child, a misdemeanor, punishable by up to 364 days in jail.

Michael Gagnier has been held at Androscoggin County Jail in Auburn in lieu of $25,000 cash or $50,000 worth of real estate. Conditions for his release include no possession or use of alcohol or illegal drugs and no contact with the victim or with his wife. He also must have no contact with anyone under age 16, the judge said.

Christal Gagnier was released on $5,000 cash bail.

cwilliams@sunjournal.com