Charges are expected later in the day against four black suspects, Chicago police spokesman Anthony Guglielmi told The Associated Press.
He acknowledged that the suspects made "terrible racist statements" during the assault, but that investigators believe the victim was targeted because he has "special needs," not because of his race. But he said authorities are still looking at whether the attack falls under hate crimes statutes.
Guglielmi said it's possible the suspects were trying to extort something from the victim's family. Investigators said the victim was with his attackers, including one who was a classmate, for up to 48 hours, and the attack left him traumatized.
Excerpts of the video posted by Chicago media outlets show the victim with his mouth taped shut slumped in a corner as at least two assailants cut off his sweatshirt with a knife, as others taunt him off camera. The video shows a wound on the top of the man's head, and one person pushing the man's head with his or her foot. A red band also appears to be around the victim's hands.
Off-camera, people can be heard using profanities about "white people" and Trump. At least one woman is shown in the video.
The victim is a suburban Chicago resident who Police Superintendent Eddie Johnson said has "mental health challenges." In a news conference Wednesday, Johnson described the video as "sickening."
"It makes you wonder what would make individuals treat somebody like that," he said.
The investigation began Monday after officers found a man who "was in distress and was in crisis" walking on a street on the city's West Side, Capt. Steven Sasso said. The man was taken to a hospital and it was later discovered that he had been reported missing from an unidentified suburb.
At about the same time, police took several people into custody at a nearby address where they found signs of a struggle and property damage. Investigators determined that the missing man had been at the same address.
When asked Wednesday about the racial comments on the video, Cmdr. Kevin Duffin said the four people in custody were "young adults and they make stupid decisions." Investigators will have to determine whether the racial remarks were "sincere or just stupid ranting and raving" when considering a potential hate crime charge, Duffin said.
The victim was with his attackers for 24 to 48 hours before police found him, and the episode has left him shaken, according to Duffin.
"He's traumatized by the incident and it's very tough to communicate with him at this point," he said.
The victim was a classmate of one of the attackers and initially went with that person voluntarily, Duffin said.
Police haven't identified the individuals in custody, but said three are Chicago residents and one is from suburban Carpentersville. Guglielmi said the suspects are all age 18 or older, and that police were working with prosecutors on Thursday "to build the strongest case."
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