WATCH: Chicago police arrest 4 African-Americans after brutal attack on mentally disabled teen goes viral

Police in Chicago have arrested four people for allegedly being involved in assault on an 18-year-old mentally disabled man and broadcasting it on Facebook Live, reports the Chicago Tribune.

The victim, who reportedly knew one of his attackers, is white and his assailants are black.

Called the attack "sickening," Chicago Police Superintendent Eddie Johnson held a press conference Wednesday night to announce the arrest, but admitted authorities are still formulating charges against the attackers, including hate crime charges.

"It's sickening. It makes you wonder what would make individuals treat somebody like that,” Johnson said of the video. “I've been a cop for 28 years and I've seen things that you shouldn't see. 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."

In the video the attackers can be seen cutting the shirt off of the gagged man, hacking off his hair with a knife, choking him and standing on his head while shouting "F*ck white people" and "F*ck Trump."

Police began their search for the assailants after being alerted to the video that was posted on Facebook. The original video has since been removed, although it has been copied to other social media platforms.

The video can be seen below, with the warning that it is appalling and highly upsetting: