A combination photo shows four people charged with felonies for the beating of a man with mental health issues, L-R: Brittany Covington, 18, Jordan Hill, 18, Tanishia Covington, 24, and Tesfaye Cooper, 18, shown in Chicago Police Department photos released in Chicago, Illinois, US January 5, 2017. [Photo/Agencies]

The victim, who was not identified, was picked up on Saturday by one of his abductors in a northwestern suburb of Chicago where his parents had dropped him off at a McDonald's restaurant, police told a news conference.

Jordan Hill, Tesfaye Cooper and Brittany Covington, all 18, were each charged with aggravated kidnapping, hate crime, aggravated unlawful restraint, aggravated battery with a deadly weapon and residential burglary, prosecutors said.

Tanishia Covington, 24, faces the same charges, except for residential burglary. Hill was also charged with robbery and possession of a stolen vehicle.

The victim, 18, was missing for days, police said.

They said Hill was an acquaintance of the victim, and that he picked him up in a stolen van. While the victim's parents reported him missing, their son and Hill spent the next two days together, visiting friends and sleeping in the van.

On Tuesday, a "play fight" between the two in the Covington sisters' apartment escalated, Kevin Duffin, a police commander, said at the news conference.

The victim was tied up for four or five hours, gagged and beaten. His scalp was cut and he was forced to drink toilet water, Duffin said.

In the Facebook Live video, the attackers could be heard making comments about "white people" as the victim cowered in a corner, his mouth taped shut.

At least one of the attackers could also be heard saying obscenities about President-elect Donald Trump. Police said they did not know whether the victim was a Trump supporter.

"Let me be very clear, the actions in that video are reprehensible," Police Superintendent Eddie Johnson said.

Police officers located the victim on Tuesday after neighbors complained about noise coming from the apartment. He was outside in freezing weather wearing only a tank top, shorts and sandals, police said.

He was taken to a hospital and later released. Members of the public alerted investigators to the Facebook Live video.

The four suspects are due to appear in a Chicago bond court on Friday.