Four people are in detention after a “disturbing” and “brutal” video displaying a man with “mental health challenges” being tied up, beaten and tortured was streamed live on Facebook “for the entire world to see,” Chicago Police say.

Police told WFLD-TV they were alerted of the video Wednesday afternoon and the incident took place Tuesday. The group appearing to take the man hostage are black, while the victim is white, but police say they haven’t decided if the case will be investigated as a hate crime.

In the video, one of the attackers can be heard yelling, “f*ck Donald Trump n*gger, f*ck white people, boy.”

Police told WBBM-TV the victim has special needs and was a high-risk missing person from northwest suburban Crystal Lake.

The victim, who can be seen in the video being kicked and punched and cut on his scalp, was hospitalized, police said. He was recovering on Wednesday. The names of those in custody have yet to be released.

NOW: Chicago Police Supt talking about alleged kidnapping and torture live-streamed on Facebook. 4 people in custody. @cbschicago pic.twitter.com/mRRvM2H34X

— Audrina Bigos (@AudrinaBigos) January 5, 2017

The 18-year-old man was last been seen by his parents on December 31, and they told police they received texts from his liberator’s while he was with them, WLS-TV reports. His parents live in Streamwood, Illinois, a suburb in Cook County, and police there are also looking into the case.

Police told WBBM the victim traveled to Carol Stream to meet a friend, and they ended up in a stolen car, which was driven to the West Side of Chicago, where the attack took place in a home in the 3400 block of Lexington Avenue.

The 30-minute video was originally posted on Facebook Live by Brittany Herring, but has been deleted. It has since been re-uploaded on Youtube and elsewhere.

The four people in custody have not been formally charged yet. The person who posted the video on Facebook was also arrested.

While on the beat officers observed a disoriented male walking 3400 W. Lexington on January 3, 2017 who was then taken to an area hospital for immediate attention. At 5:26 p.m. officers then answered a call of battery at a residence on the 3300 block of W. Lexington where they discovered signs of a conflict and damage to the property and were able to link this evidence to the disoriented male. Officers subsequently became aware of a social media video portraying a beating of an adult male which is believed to be the same person. At this point CPD believes the video is convincing and detectives are questioning people of interest in the case. The victim, whom CPD believes is from a neighboring suburb, was transported to an area hospital in stable condition. The investigation is ongoing.

Police held a press conference Wednesday night to address the incident. You can watch that below:

CPD press conference regarding disturbing live social media video depicting a battery ; victim was tied up https://t.co/jDrjfz4sJV

— Chicago Police (@Chicago_Police) January 5, 2017

“I’ve said time and time again that if you commit an act of violence in the city of Chicago, you will feel the full weight of the Chicago Police Department,” Superintendent Eddie Johnson said at the press conference. “And tonight, four individuals have experienced the consequences of their actions.”

Police say officers found the man, a suburban resident reported missing, yesterday. He may have been kidnapped. Video streamed online.

— Mitch Smith (@MitchKSmith) January 5, 2017

Captain Steven Sesso, the commanding officer of the 11th District, said “alert 11th District officers encountered” the victim and it “didn’t feel right, the situation. They saw clearly this individual was in distress, that he was in crisis. And they cared enough to do something about it.”

Commander Kevin Duffin, who leads the detectives investigating the incident, said three of the suspects are Chicago residents and the fourth is from Carpentersville, Illinois. The Cook County State’s Attorney’s Office was interviewing the victim and charges were expected to be filed by Thursday.

The victim is white. Anti-white and anti-Trump messages are heard in video of beating. Police say the four suspects are African-American.

— Mitch Smith (@MitchKSmith) January 5, 2017

Duffin said the individual is “an acquaintance” of one of the people in custody, and they “met in the suburbs, the subjects then stole a van out in the suburbs and drove him into Chicago.” He knew one of the subjects from high school, police said.

He said they are still talking to the individual and there is “quite a possibility it is a kidnapping.”

Duffin said the victim is “traumatized by the incident” and it is challenging for detectives to communicate with him.

Police said the victim was with the group for at least 24 hours to as many as 48 hours. Duffin said it appears he was finally just cut free and let go, which is when he was discoverd by patrol.

s to whether it was a hate crime, Johnson said they are still investigating and if the facts lead them in that direction, they will file hate crime charges.

“Kids make stupid mistakes, I shouldn’t call them kids, they are legally adults, but they are young adults and the make stupid decisions,” Duffin said of the vulgar remarks about Trump and white people. “That certainly will be part of whether or not we seek a hate crime, determine whether or not this is sincere or stupid ranting and raving.”

The suspects are 18, Duffin said.

“It’s sickening,” Johnson said of the video. “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 you shouldn’t see in a lifetime, but it still amazes me how you still things you just shouldn’t. I’m not going to say it shocked me, but it was sickening.”

Johnson said the incident doesn’t appear to be politically motivated.

“I think part of it is just stupidity,” Johnson said. “People ranting about something they think might make a headline. At this point we don’t have anything concrete to point (toward a hate crime) but we’ll keep investigating and let the facts guide us on how this concludes.”

Johnson said he can’t connect what happened in the video to Trump talking and tweeting about violence in Chicago.

“If you looked at the video, it was just stupidity,” Johnson said.

The video begins with the band of apparent captors yelling at the tied up man. They cut the sleeves of his sweatshirt as one says they’re going to make him “butt ass naked.”

Chicago Police say the man tortured has “mental health challenges.” He may have been held hostage for 24-48 hours. @cbschicago @cbsnews pic.twitter.com/nLjA8pcTsW

— Audrina Bigos (@AudrinaBigos) January 5, 2017

The woman filming the video then appears to realize she’s on Facebook Live, but continues recording as she smokes. The video also includes many remarks to drinking and getting drunk.

The group makes several references to Donald Trump at the beginning of the video, yelling his name and cursing him.

The video was quickly spread around on social media, and #BLMKidnapping was trending on Twitter by Wednesday night.

In mid-November, four people were arrested after a man was attacked and robbed in Chicago while bystanders yelled “don’t vote for Trump,” DNAInfo reported. That attack was also caught on video:

The 50-year-old victim later said he voted for Trump, but did not have a bumper stick on his car or anything else to identify him as a Trump voter, according to DNAInfo.

Johnson said he didn’t know of any other incidents involving assaults targeting Trump supporters in the city.

Chicago police chief calls video of alleged Facebook Live torture “sickening.” https://t.co/uwa0lx5ofh pic.twitter.com/9DcBBjlSHp

— WGN TV News (@WGNNews) January 5, 2017

Facebook said it deleted the original video from the social media site.

“We do not allow people to celebrate or glorify crimes on Facebook and have removed the original video for this reason,” the company said in a statement to The Guardian. “In many instances, though, when people share this type of content, they are doing so to condemn violence or raise awareness about it. In that case, the video would be allowed.”

Police in Streamwood now say the victim’s captors were texting his parents “claiming to be holding him captive.”

— Sam Charles (@samjcharles) January 5, 2017

It is also not the first time a disturbing Facebook Live video has made the news in Chicago. In two isolated occasions, men were shot while streaming live video on Facebook. One man was killed and the other was seriously wounded.