Chicago police say charges are expected against four people who police say beat a man in an assault that was broadcast live on Facebook.

The victim is a suburban resident who Police Superintendent Eddie Johnson says has "mental health challenges."

Johnson called the attack and the video "sickening" at a news conference Wednesday. Johnson questioned why individuals would treat someone so harshly.

Police Cmdr. Kevin Duffin said Wednesday that he anticipated charges within 24 hours.

While police officials did not confirm the races of the suspects or victim, video from Chicago media outlets appeared to show someone off-camera using profanities about "white people" and President-elect Donald Trump.

Police say it's too soon to determine whether the attack was racially motivated.

Police haven't identified the individuals in custody, but say three are Chicago residents and one is from suburban Carpentersville.