AUBURN — A Turner man called police on Saturday and confessed he killed his wife, according to court documents.

An Androscoggin County Sheriff’s deputy, who happens to be a nephew of the man, was dispatched to the man’s home. There, Brian Nichols, 45, said: “It’s over. I did it.”

When asked where his wife was, Nichols said: “She’s in bed, dead. I shot her.”

Nichols appeared in Androscoggin County Superior Court on Monday morning. Wearing a bright orange jail suit, his wrists and ankles shackled, he stood shaking visibly while facing the judge.

He is charged with one count of murder.

The court ordered a mental examination at the state’s hospital in Augusta. The court also will schedule a bail hearing.

Nichols was held Monday without bail at Androscoggin County Jail.

Nichols told his nephew, Deputy Kevin Nichols, that he used a .30-.30 caliber rifle and told him where to find it.

He said his wife, Jane Tetreault, 38, was having an affair.

The nephew followed one of Nichols’ sons into the home at 225 East Hebron Road and saw Tetreault in bed, dead from an apparent gunshot to the head.

A spokeswoman at the Maine Office of the Chief Medical Examiner on Monday confirmed the cause of death as “gunshot wound to the head and neck.” It was homicide, she said.

Travis Nichols, 17, was at home at the time police arrived at the house. His brother, Tyson, 15, was at a friend’s house, an affidavit in court documents said.

Travis Nichols told police he believed his father suffered from bipolar disorder. He recently had been accusing Tetreault of having an affair with a man who was a client at Tetreault’s workplace, Service Master. He also was a co-worker of hers at L.L. Bean.

Nichols was also employed at the Lewiston franchise of ServiceMaster Co., according to Steve McCausland, spokesman for the Maine Department of Public Safety.

Brian Nichols began stalking his wife, Travis Nichols told police. Travis called his mother at work on Friday shortly before midnight. She said Brian Nichols also was at the office. Travis Nichols hung up and went to sleep. He woke up later to his mother’s screams. He thought he could hear his father pacing around the house, but drifted off to sleep again. He awoke to police sirens. He got out of bed and went to his mother’s bedroom. He pulled back the sheets and discovered her bloody body. He ran outside and began yelling at his father.

“What did you do in there?” Travis Nichols said. “You killed my mother. She’s in a pool of blood, dead.”

Police said Brian Nichols’ call reporting the shooting came in at 3:30 a.m. Saturday.

Earlier in the week, Brian Nichols had gotten mad and had thrown his cell phone on the ground, breaking it. On Friday, he asked Travis Nichols to fix it and became angry when he couldn’t.

Travis Nichols told police that his mother recently had been sleeping at the ServiceMaster office and not going home until early morning because she was afraid of being at home with her husband.

Tyson Nichols told police that he received a text message from his father at 2:26 a.m. Saturday saying that his mother was “downloading porn on her computer and she’s gonna blame me.” Less than two hours later, Tyson Nichols got a call from his brother, saying their mother was dead.