AUBURN – A Lewiston man charged with murder in connection with the strangulation death of his mother is expected to plead guilty to manslaughter next month.

Both Matthew Audet, 23, of 101 Birch St. and his wife, Kayla, may have had sexual relationships with his mother, Debra, who lived with the couple, police said. Kayla Audet told her husband she was planning to leave him, and the two had argued about it shortly before Debra Audet’s death, police said.

Matthew Audet has been held at Androscoggin County Jail since his arrest in March. He was later indicted on a murder count by an Androscoggin County grand jury. He remained in jail in lieu of $100,000 cash bail.

Assistant Attorney General Lisa Marchese said Monday that a Nov. 4 hearing is scheduled in Androscoggin County Superior Court. Her office reached an agreement with Audet for him to plead guilty to manslaughter, according to documents filed with the court clerk. In exchange, her office would dismiss the murder indictment against him. No agreement was reached on a sentence, which would be decided by a judge at a January hearing after both sides argued their respective recommendations, Marchese confirmed.

Audet’s attorney, Justin Leary, could not be reached Monday for comment. Attorneys for both sides had talked to a judge last week about a possible agreement, according to court records.

Audet’s wife, Kayla, told police she saw her husband choking his mother on a mattress on the floor of their apartment. An autopsy revealed a broken bone in the front of her neck and other injuries consistent with strangulation. Kayla Audet told police her husband confessed killing his mother afterward as she prepared to leave him.

Matthew Audet called police shortly before midnight on a Sunday in mid-March to report that his mother had stopped breathing. He said she had choked herself.

Audet told police he had been drinking beer, wine and liquor with his mother earlier that night in their apartment. They had reportedly been arguing about her sexual relationship with Audet’s wife, one that reportedly began when Audet was away serving in the military, according to a police affidavit.

A neighbor told police Audet had been sexually involved with his mother since he was 8 or 9 years old, court records said.

Audet and his mother had a troubled history dating back to when they lived in mobile home in Poland. Debra Audet recently was being treated for cancer.

Court records show Audet was seeking public money to pay for a prominent Maine psychologist who often consults in murder cases, and for a private investigator.