Hate crime and assault charges have been filed against four people over an attack on a man with special needs which was streamed live on Facebook.

Prosecutors in Cook County, Illinois, announced charges against three 18-year-olds — Jordan Hill, Brittany Covington and Tesfaye Cooper — and 24-year-old Tanishia Covington.

The group have also been charged with kidnapping, aggravated unlawful restraint and assault with a deadly weapon.

Three of them have additionally been accused of burglary.

The charges stem from an incident which lasted 48 hours and targeted a white man police described as having “mental health challenges”.

All those charged are black.

“He’s traumatised by the incident, and it’s very tough to communicate with him at this point,” police commander Kevin Duffin said.

Excerpts of the video show the victim with his mouth taped shut slumped in a corner.

He has a wound on his head, and a red band appears to be around his hands

Earlier, police superintendent Eddie Johnson said four people had been arrested over the “sickening” footage, in which the man’s tormentors could be heard saying “F*** Donald Trump” and swearing about “white people”.

The police said the victim was an 18-year-old white man from suburban Chicago who had been reported missing.

Officers spotted him on Tuesday in a violent neighbourhood on Chicago’s West Side and recognised that he was in distress, the police said.

They sought treatment for him at a hospital and connected the beating to the four people, who were taken into custody later that day near where the man had been found.

Video

A roughly 30-minute video clip shared widely online appeared to show a Facebook livestream of the assault.

A group can be seen taunting and physically assaulting a man amid cursing and laughing.

Much of the video focuses on one woman as she rambles, at times incoherently.

The video begins with a shot of that woman before turning to the victim, who is seated in the corner of a room with his mouth covered.

The woman laughs as two men cut the sleeve of the victim’s shirt. One of the men yells epithets about Trump and “white people”.

Later, a man cuts a patch of hair from the victim’s head, appearing to draw blood in the process.

Investigators had said that they were not yet sure of a motive but that they could pursue hate crime and kidnapping charges if the evidence warranted.

The victim knew one of his attackers, the police said, and had been taken from the suburbs to the city and held for some time before the beating was streamed online.

‘Brazenness of the offenders’

“Images in the video put on display the brazenness of the offenders who assaulted the victim and then broadcast it for the entire world to see,” Mr Johnson said.

The victim, whom the police did not name, was hospitalised for undisclosed injuries but had been released by Wednesday evening and was speaking with investigators.

The police said he was traumatised and initially had trouble communicating with detectives.

The assault comes at a time of relentless violence in Chicago.

In a Twitter post this week, Mr Trump cited Chicago’s 762 homicides last year and suggested that the city should seek federal help if local efforts to control the violence continued to be ineffective.

Mr Johnson declined to speculate on whether the president-elect’s Twitter message and the beating on the video were connected.

Video of the incident was initially posted on Facebook, but was later removed from the social media site.

A Facebook spokesman said the company removed the video because it does “not allow people to celebrate or glorify crimes on Facebook”.

Agencies