Chicago police said Wednesday night that four teens are being held and questioned in connection with a Facebook Live video showing a group of people beating and cutting a teen who appeared bound and gagged as they shouted “F--- Donald Trump.”

Chicago Police Supt. Eddie Johnson called the video a "brutal act" that was "broadcast for the entire world to see." He said the victim has "mental health challenges."

NBC News reported that officials said they expect to file charges against the four 18-year-olds, two men and two women, within the next 24 hours.

Police said officers on patrol found a disoriented man walking Tuesday afternoon in the 3400 block of West Lexington in the city's Homan Square neighborhood. The man was transported to an area hospital for treatment.

Then, just before 5:30 p.m., officers responded to a battery at a residence in the 3300 block of West Lexington, where they discovered signs of a struggle and damage to the property -- a scene they linked to the disoriented man.

Officers later became aware of social media video depicting “a battery of an adult male which is believed to be the same individual,” police said in a statement Wednesday.

Authorities said the video, which shows a group of black men and women kicking, cutting and slapping a white man, who at one point appears to be bound and gagged, is credible. The video was posted around 2 p.m. Tuesday and had been seen more than 62,000 times before it was removed from Facebook.

In the footage, some in the group can be heard saying "F--- Donald Trump" and "F--- white people."

The victim is an 18-year-old man from northwest suburban Crystal Lake who had been reported missing and "has mental health challenges," police said. His parents reported him missing late Monday, telling police they had not heard from him since Dec. 31, when they dropped him off at a McDonald's at Schaumburg and Barrington Roads, according to a release from Streamwood police.

His parents began receiving text messages from persons claiming to be holding him captive, authorities said, and officials discovered the Facebook video while investigating the source of the messages.

Police said the teen was "extremely traumatized" but has been released from the hospital.

Authorities believe he knew one of the suspects and had gone with that person willingly before he was eventually brought to the city in a stolen van and held against his will.

He had been with the suspects for at least 24 hours, authorities said.

"It's sickening," Johnson said. "It makes you wonder what would make individuals treat someone like that."

Police are investigating whether the attack was a hate crime, though they have not yet said that it is one. Commander Kevin Duffin told reporters that it may have been people "ranting about something they think might make a headline."

When asked if the attack was politically motivated, Johnson said "at this point we don't have anything concrete to point in that direction."