Updated 10/27/11 – 3:09 p.m.

BURNHAM, Ill. (CBS) – An off-duty Harvey police officer shot and killed a man who opened fire in a south suburban bar overnight.

WBBM Newsradio’s Mike Krauser reports that, around 3:40 a.m. Thursday inside the Little Brown Jug at 14540 Torrence Av. in Burnham, a man started something with an off-duty police officer at the bar.

The suspect, later identified as 34-year-old Ronnie Bobo, opened fire inside the tavern and wounded one man, police said.

LISTEN: WBBM Newsradio’s Mike Krauser reports

Bobo then began firing at the off-duty officer inside the bar after the officer had identified himself as a law enforcement official, police said. The officer was not hit but Bobo ran out the door and began firing rounds into the front window of the bar.

The officer chased the Bobo outside and they exchanged gunfire. The officer struck the man several times.

“The officer performed commendably,’’ Burnham police Chief Peter Belos said. “The suspect had no regard for anyone’s life and the officer prevented further death and injuries.’’

A witness who was in the Little Brown Jug at the time said “dude went crazy.”

“I just seen a crazy shooting, it was real crazy,” said the witness, who asked to be identified only as “Red.” He was questioned by police for several hours after the shooting.

Bobo was pronounced dead at St. Margaret’s Hospital in Hammond, Ind. at 6:30 a.m.

The man who had been shot by Bobo was not seriously injured and has been released from the hospital. The police officer was not wounded in the shootout.

About 20 people were at the bar at the time. The front window was broken by gunfire and there appeared to be bullet holes in the stucco.

Belos said police do not know what prompted Bobo to start firing and said they have not had any similar incidents at the bar.

(The Sun-Times Media Wire contributed to this report.)