SAN LUIS OBISPO (CN) - Convinced that the "spirit of the wolf" was inside of him, Mark Andrews left piles of dirt and flour on a neighbor's porch in 2009, his attorney said, hoping to humiliate what he believed was a vampire living inside.
Four years later, Andrews allegedly believed a different neighbor was a vampire. And when he knocked on that door, Colleen Barga-Millbury - unlike the first neighbor - made the mistake of opening it.
Andrews, 51, is on trial in San Luis Obispo County, accused of fatally shooting 52-year-old Barga-Milbury two times with a lever-action .30-30 rifle.
While he has a documented 20-year history of believing he is a werewolf and has been committed to psychiatric hospitals numerous times, the standard for proving an insanity defense in California may make it difficult for him to avoid prison time.
"The defendant was not delusional or psychotic on the day of the murder," deputy district attorney Matt Kraut told jurors this week. He said that Andrews knew that what he did was wrong.
But Andrews' attorney Ilan Funke-Bilu told jurors that aside from mental illness, Andrews had no motive to kill his neighbor.
"There were no known conflicts between Ms. Barga-Milbury and my client," he said.
Police were dispatched to Barga-Milbury's Atascadero home on May 22, 2013. Hours after she was shot, her 15-year-old son, who has autism, found her lying just inside the entrance to their home.
"Wake up, Mom!" the boy pleaded, according to witness Russell Moore, who gave the boy a ride home when Barga-Milbury failed to show up at her son's school.
Investigators interviewed several neighbors, including Andrews, who lived with his mother.
Andrews did not seem psychotic or delusional, investigators testified. Hours after the murder, they later learned, he bought beer at a local convenience store.
The day after the shooting, as investigators scoured Barga-Milbury's home for evidence, a television reporter seeking to interview neighbors approached Andrews, as he sat outside his home on a plastic chair.
The person responsible, he told KCOY-TV reporter Leah Masuda, was an "animalistic bastard."
"I'm just at a loss of words right now," he told Masuda in the broadcast report. "I don't know what to say."
"We were friends for a short while," he added. "She was friendly, courteous, outgoing, active."
Police did not have any suspects until they got a tip from a caller who said Andrews was mentally ill.
Investigators returned to Andrews, when he told them he had guns in his home, they asked for permission to search the house. In his bedroom they found a stocked rifle cabinet, spent shell casings and a nutcracker doll.
Investigators had seen several nutcracker dolls in Barga-Milbury's home. Wayne Drew, Barga-Milbury's boyfriend, said her son collected nutcracker dolls.
Andrews was not told he was under arrest, but police asked him to ride with them to the nearby police station. While waiting in an interrogation room alone, a video camera recorded Andrews speaking to himself. A lip reader hired by the prosecution translated his lip movements, according to a court document.
"Mark, they want to help you with your struggle," he said. "They want to help you, Mark. They arrest you only to help you."