A man died Tuesday night after Chicago police shocked him with a Taser stun gun because he was combative during an arrest on the West Side, authorities said Wednesday morning.

Police sources say the man was on drugs and "acting suspiciously," walking away from police near the 2600 block of South Trumbull Avenue in the South Lawndale neighborhood. When police tried to stop him, he was combative, and was sprayed with a chemical spray and shocked with the gun, sources said.

Officer John Henry said the man "was Tasered on the West Side after resisting arrest, and becoming combative and violent while being taken into custody."

Roberto Gonzales, whom the Cook County medical examiner's office said was 24, but police and neighbors said was 37, was pronounced dead at 8:15 p.m. in Mt. Sinai Hospital. The man has a criminal history and was a known gang member, police sources said.

Ilana Rosenzweig, chief of the Independent Police Review Authority, an agency that probes possible misconduct of Chicago police officers, said the agency was notified of the incident Tuesday night and was identifying witnesses.

"We will not be able to complete our investigation until we get a complete autopsy report," Rosenzweig said.

An autopsy for Gonzales is scheduled for later Wednesday.

The Taser used was one of the department's newer models, equipped with a camera that allows the incident to be videotaped. Investigators will be reviewing that tape, said Monique Bond, spokeswoman for the Chicago Police Department.