A sickening beating and torture of a mentally disabled Illinois man was live-streamed on Facebook – with the assailants shouting anti-Donald Trump and racial obscenities during the attack.

Police Superintendent Eddie Johnson said at a news conference Wednesday four suspects are in custody. Formal charges have not been filed, and no determination was immediately made on whether the attack was racially motivated.

The victim was a high-risk missing person from the Chicago suburb of Crystal Lake, CBS News reported.

The video of the beating lasts about 30 minutes and shows the victim tied up and with his mouth taped shut, according to CNN, which posted a portion of the footage.

CBS News reported the filming shows the victim being punched and kicked, peppered with cigarette ashes, and cut on his forehead with a knife. Others in the video can be seen laughing and eating during the gruesome attack.

In the video, the assailants can be heard yelling "F— Donald Trump" and "F— white people," CNN reported.

The attack occurred Tuesday in an apartment on Chicago's West Side, CBS News reported.

ABC affiliate WLS reported it was believed the victim was held for 24 to 48 hours before being let go.

According to the Chicago Tribune, the victim was found wandering in shorts with another man. He was taken to a hospital, where he was treated and released, then reunited with his parents.

"It's sickening," Johnson told the Tribune. "It makes you wonder what would make individuals treat somebody like that. I've been a cop for 28 years and I've seen things that you shouldn't see. It still amazes me. . . . I'm not going to say it shocked me, but it was sickening."

The Associated Press contributed to this report.