Empire actor Jussie Smollett “took advantage of the pain and anger of racism to promote his career”, Chicago police superintendent Eddie Johnson has said.

Mr Johnson said Smollett sent a racist and homophobic threatening letter to himself at the Fox studio lot before an alleged attack.

Speaking at a news conference, Mr Johnson said Smollett was dissatisfied with his salary.

Smollett, who is accused of filing a false police report, was charged on Wednesday with felony disorder conduct and turned himself in early on Thursday.

The actor told police he was attacked by two masked men as he was walking home from a Subway sandwich shop at around 2am local time on January 29.

Smollett, who is black and gay, said they beat him, made racist and homophobic comments, poured some unknown chemical substance on him and looped a rope around his neck before fleeing.

Police said the investigation shifted after they questioned two brothers who were in the area that morning.