An Atascadero, CA man accused of gunning down his neighbor has believed he was a werewolf for about 20 years, a forensic psychologist testified Tuesday.

The District Attorney’s Office says Mark Andrews, 51, committed murder when he shot Colleen Barga-Milbury, 52, twice on May 22, 2013. But Andrews has pleaded not guilty by reason of insanity.

During trial testimony Tuesday, defense witness Carolyn Murphy, a forensic psychologist who interviewed Andrews for roughly five hours, said she reviewed his mental health records, which includes seven or eight hospitalizations.

Murphy said Andrews has schizophrenia and suffers from fixed delusions, which she defined as false beliefs that continue over time.

The first record of Andrews believing he was a werewolf, she said, dates to 1996, though she suspects he had that same delusion during his first psychotic episode three years earlier.

“(He believes) he transforms into a werewolf,” she said, and “holds the spirit of the wolf.”

Murphy said Andrews believed the voice of God commanded him to kill Barga-Milbury, whom he believed was a vampire.

In 2009, according to court records, Andrews believed a different neighbor was a vampire. Andrews left mounds of dirt and flour on that neighbor’s door and once pounded on the neighbor’s door, calling her a “bitch,” though she didn’t answer.

At his home, according to police reports, police found two lists of names, several marked “hate with death.”

Murphy testified that she asked Andrews why he didn’t kill the neighbor from 2009.

“God didn’t tell him to kill her,” she said.

While Murphy said she believes Andrews was delusional when he shot Barga-Milbury, deputy district attorney Matt Kraut questioned that conclusion.

During his cross-examination, he suggested that various people who had interactions with Andrews before and after the murder did not detect psychotic behavior, including police who interviewed him after the shooting, jail staff and the defendant’s treating psychiatrist, who had described Andrews as relatively stable three months earlier.

Murphy said sometimes schizophrenics can control their symptoms and appear more normal, especially if they are taking their medications. Andrews’ mother, Carol Andrews, has said that her son was not taking his medications regularly closer to the time of the killing, Murphy said. - San Luis Obispo