Scott Ostrem, 47, leaves a hearing in Adams County, Colorado on Friday
The stepsister of a man charged with fatally shooting three people at a Colorado Walmart said he has been tormented by voices in his head since taking LSD nearly 30 years ago - an event she said radically changed his behavior and personality.
'When he came home, he was terrified. He had voices in his head. Demons,' Michelle Willoughby told The Denver Post in an interview posted online Monday.
Prosecutors filed multiple counts of first-degree murder and attempted-murder charges Monday against Scott Ostrem, 47, Willoughby's stepbrother.
Ostrem is accused of walking into a Walmart in the Denver suburb of Thornton on Wednesday and fatally shooting a woman and two men. Prosecutors still have not offered any clues into possible reasons for the attack.
'Can't talk about a motive yet, thanks,' Adams County District Attorney Dave Young said Monday.
Willoughby, who lives in Cocoa Beach, Florida, said she does not know what might have triggered the shooting because she has not been able to speak with Ostrem.
But she said he had been outgoing, sociable and athletic before taking LSD at a party in 1988, and afterward he became a recluse haunted by voices saying the devil was after him.
The family contacted a hospital, and Ostrem underwent a drug intervention but did not get psychological treatment, she said.
Ostrem was frequently counseled by a Catholic priest who placed a crucifix on his forehead, commanded demons to leave his body and asked God to silence the voices, Willoughby said.
She said the priest has since died and she does not recall his name.
Before the shooting: Suspect Scott Ostrem at a Walmart in Thornton, Colorado
The National Institute on Drug Abuse says the long-term effects of