WASHOUGAL, Wash. – A Washougal man accused of murdering his grandmother appeared in court Tuesday and documents paint a grisly sequence of events March 6.

Benjamin Wayne Walker, 27, has been accused of murdering his grandmother, Joan Walker.

Walker went to the police station in Washougal shortly before 6 a.m. on Monday and confessed to the killing, according to a probable cause affidavit.

Walker said that the evening of March 5 and the following morning, he drank a six-pack of 32-ounce beers. He was angry with his grandmother and "decided her and his fate."

Joan Walker continually chastised him for leaving lights on and taking long showers she thought was a waste of hot water, he told police.

He went into her bedroom. She was asleep but realized he was there. He started to choke her and suffered minor injuries as she fought for her life. Walker had scratches to his chin and mouth, the affidavit said.

He told police he used a knife from the kitchen to slit her throat to make sure she was dead.

The Clark County Medical Examiner determined Joan Walker died of strangulation and several sharp force injuries to the neck. Her manner of death was homicide.

After washing his hands, Benjamin Walker left his wallet and cell phone in the garage where he sleeps and went to the police station to confess, the affidavit said.

Neighbor Bill Fleger knew Joan Walker for 20 years.

"She kinda watched the neighborhood," he said. "Yeah, she was a real nice person. Always give my wife fruits and vegetables in the summertime."

He said recently, she had been letting a young man live in her garage.

"He mowed our grass every other week and he's real quiet and respectful," he said of the grandson. "That's why we didn't think he was the one who did it . . . until he did."