Updated at 11:45 A.M

Four people are in custody in Chicago over what police say is a beating live-streamed on Facebook in which a man was tied up, hit and cut with a knife by several assailants.

Authorities say the victim, who had been reported missing before the attack, has “mental health challenges.” He was encountered by police on Tuesday evening and is recovering in the hospital.

The Facebook stream has been deleted. But multiple outlets have posted videos they identify as archives of the stream, recorded by a woman who frequently turns the camera on herself. The clips show multiple people taunting, threatening and hitting a man who is tied up in a corner. At least once, a man uses a knife to cut the victim’s hair, cutting into his scalp.

On the video, the assailants, who are black, say “f*** Donald Trump” and “f*** white people.” They force the victim, who is white, to say “f*** Donald Trump,” as well.

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Police say it’s too soon to identify whether the beating was a hate crime or was racially motivated.

Detective Kevin Duffin said at a news conference late Wednesday that investigators are working to determine whether the statements on the video are “sincere or just stupid ranting and raving.”

CPD press conference regarding disturbing live social media video depicting a battery ; victim was tied up https://t.co/jDrjfz4sJV

— Chicago Police (@Chicago_Police) January 5, 2017

The Associated Press reports that police say they don’t believe the victim was targeted because he was white:

“Police spokesman Anthony Guglielmi said Thursday morning that charges are expected soon against four black suspects. Guglielmi says the suspects made ‘terrible racist statements’ during the attack, but that investigators believe the victim was targeted because he has special needs, not because of his race.

“Guglielmi says it’s possible the suspects were trying to extort something from the victim’s family.”

As for the remarks about Donald Trump, Cmdr. Kevin Duffin said at a news conference late Wednesday that investigators are working to determine whether the statements are “sincere or just stupid ranting and raving.”

Chicago police found the victim in distress on the street before they were aware of the existence of the Facebook live stream, authorities said at the news conference. The four suspects were arrested after police were called to a residence near where they’d found the man and then connected the incident and the location.

The victim, a resident of a Chicago suburb, apparently spent at least 24 hours in the company of his alleged assailants — one of whom he knew from school, police say. He had been reported missing on Monday. Police say he traveled into the city with his acquaintance in a stolen van and that it’s not yet clear whether a kidnapping was involved.

A GoFundMe account for the victim has been set up; a public relations representative for GoFundMe says the website will be working with the campaign organizer to ensure all money raised reaches the victim.

Police Superintendent Eddie Johnson highlighted the “brazenness” of the assailants, for not just carrying out the attack but broadcasting it “for all to see.”

“It’s sickening,” he said. “It makes you wonder what would make individuals treat somebody like that. I’ve been a cop for 28 years — I’ve seen things that you shouldn’t see in a lifetime — but it still amazes me how you still see things that you just shouldn’t [see].”