Four people have been arrested in Chicago (US) over a video live-streamed on Facebook, in which a bound and gagged man was assaulted.

In the video, the victim’s clothes were cut, he was peppered with cigarette ashes, and then his hair cut with a knife until his scalp bled according to foreign news.

The man being assaulted has special needs, police say. His assailants can be heard making derogatory statements against white people and President-elect Donald Trump.

However Chicago police have described the video as a “sickening” possible hate crime.

The incident took place on Tuesday in an apartment on Chicago’s West Side, a police spokesperson said.

The victim, who has special needs, was a high-risk missing person from northwest suburban Crystal Lake.

According to Chicago police the incident is under investigation and suspects are being questioned.