NILES, Mich. » A passenger accused of stabbing four people on an Amtrak train in southwest Michigan told police he began the attack after seeing another man turn into a demon, according to court documents released Monday.

Michael D. Williams was arraigned Monday on attempted murder charges and requested a court-appointed attorney. A judge entered a not-guilty plea on his behalf and ordered him held in the Berrien County jail on $1 million bond.

The 44-year-old Saginaw native is accused of stabbing a conductor and three fellow passengers Friday night when the train stopped in Niles, about 10 miles north of South Bend, Indiana. Police rushed to the train and subdued Williams with a stun gun.

He later told detectives that the "guy he was talking to on the train turned into a demon and he had to fight" him, according to court documents.

Police said the victims were in stable condition. The train with 172 passengers was traveling from Chicago to Port Huron, which is 60 miles northeast of Detroit.

A sister, Tracy Williams, told The Saginaw News that she spoke to her brother last week. She said her brother seemed to be hallucinating and feared for his life as he tried to get to Saginaw.

"We were having conversations back and forth, and I said, ‘You know, Mike, this doesn’t make any sense. Why are they after you?’" Tracy Williams said. "Whatever he believed in his head was real to him. Nothing I could have said could make him think any different."

She said her brother is a military veteran who moved to Atlanta last summer to get a commercial driver’s license and work as a cross-country trucker.

"My heart goes out to the victims because they were innocent," Tracy Williams said. "He wasn’t specifically targeting them. They did absolutely nothing to deserve this."

Williams returns to court Friday.