The Oregon man accused of screaming anti-Muslim insults at two women, and then fatally stabbing two men and wounding a third as they tried to intervene on Friday, had a history of making extremist remarks, according to the police and civil rights advocacy organizations.

In a statement on Saturday, the Portland police said the attacker, who was identified as Jeremy Joseph Christian, 35, of North Portland, Ore., had been booked into the Multnomah County Jail on charges that included two counts of aggravated murder. The police also said Mr. Christian will be arraigned on Tuesday and could face additional charges.

The episode began on Friday when the three men were attacked on a Portland commuter train as they tried to calm Mr. Christian, who, the police said, was ranting and talking disparagingly about the women, one wearing a hijab. The police added that the two women, who were not injured, left the scene and were later identified and contacted by investigators.

“It’s horrific; there are no other words to describe what happened today,” Sgt. Pete Simpson, a spokesman for the Portland Police Bureau, said at a news conference. The police statement also said part of the investigation would focus on Mr. Christian’s “extremist ideology.”