CHICAGO (CBSNewYork/CBS Chicago) — Four people were in police custody in Chicago Wednesday after an assault was streamed live on Facebook.

The disturbing assault was posted as it happened Tuesday afternoon on Chicago’s West Side. The man was described as a high-risk missing person from the northwest Chicago suburb of Crystal Lake.

As WBBM-TV, CBS2 Chicago’s Audrina Bigos reported, the 18-year-old victim reportedly has mental health challenges. Police said he was terrified and traumatized Wednesday after being held hostage from one to two days.

Police in suburban Streamwood – where the victim was reported missing – told CBS Chicago the victim’s parents received text messages from the suspects claiming to be holding the young man captive.

In the video, the victim was backed into a corner where his clothes were cut, his hair was peppered with cigarette ashes, and then his hair cut with a knife until his scalp bled, CBS Chicago reported. Several people can be seen laughing and eating during the attack, in addition to making disparaging remarks about President-elect Donald Trump and using racially charged language referencing white people, CBS Chicago reported.

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“It’s sickening. It’s sickening,” Chicago Police Supt. Eddie Johnson told reporters Wednesday evening at a news conference. “You know, it’s 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 in a lifetime, but it still amazes me how you still see things that you just shouldn’t.

“I’m not going to say it shocked me, but it was sickening.”

https://twitter.com/Chicago_Police/status/816790929210306560/

Chicago Police said the incident took place in an apartment in the 3400 block of West Lexington Street in the city’s North Lawndale neighborhood.

Chicago Police Area North Cmdr. Kevin Duffin said after holding the young man hostage for 24 to 48 hours, the suspects “eventually just unbound him and let him go.”

Officers found the victim wandering the neighborhood in an obvious state of trauma, CBS Chicago reported.

Meanwhile, Chicago community activist Andrew Holmes got a hold of the video and filed a report with the police. Of the video, he told Bigos, “It makes you sick to the stomach.”

“I don’t want them to get a slap on the wrist and be put back out here on the streets, because you know, it’s just saying that this is a joke,” Holmes said.

Added Supt. Johnson: “You hear the narrative that police are backing down and not doing their jobs. This is a perfect example of them doing their jobs.”

Four people — two adult males and two adult females — were in custody late Wednesday and criminal charges were expected. It was too soon to say whether the suspects would be charged with kidnapping or a hate crime, authorities said, CBS Chicago reported.

Three of the suspects are from Chicago, and a fourth is from the far northwest Chicago suburb of Carpentersville.

“He is an acquaintance of one of these subjects,” Duffin said of a connection between the victim and the suspects, “and apparently, they met out in the suburbs. These subjects then stole a van out in the suburbs and then brought him into Chicago.”

The victim was treated and released from an area hospital following the incident, police said. He was with his parents late Wednesday.