A manhunt is underway after an off-duty Wisconsin police officer was fatally shot while trying to stop an armed robbery at a bar, authorities said.
Officer John Hetland, a 24-year veteran of the Racine Police Department, had worked the day-shift on Monday, Chief Arthel Howell said.
At 9:40 p.m. Monday, the veteran officer was off-duty when he saw an armed robbery unfolding at Teezers Tavern in Racine, about 25 miles south of Milwaukee.
(MORE: Sheriff, family grieve off-duty LA deputy's 'senseless and cowardly murder')"Hetland took immediate action," Howell said, and "during his effort to intervene," he was shot.
It is not clear if Hetland identified himself as an officer, Kenosha County Sheriff David Beth said.
Hetland is survived by two children, Racine Mayor Cory Mason told reporters on Tuesday.
"I've ordered the flags to be flown at half-staff today and until his burial," said the mayor, who had met the slain officer. "I just really can't express how deeply we feel the loss of this officer. It's been more than 40 decades since we've had a loss in this city."
"Everybody's still in shock."
(MORE: Off-duty police officer fatally shoots man at California Costco)No arrests have been made, Howell said.
The Kenosha County Sheriff's Department on Tuesday released an image of the suspect caught on surveillance video.
Authorities are canvassing the area looking for more video, Beth said.
The gun hasn't been found, the sheriff said.
(MORE: Georgia police officer dies weeks after he was shot in the face in the line of duty)A local business has offered a $5,000 reward and the FBI has offered a $20,000 reward for the capture of the suspect, Beth said.
"Officer Hetland was a trusted and highly respected member of the department, serving in various positions over the years, including an assignment as a field training officer, as well as a member of the Greater Racine FBI Gang Task Force," the chief said in a statement on Tuesday.
ABC News' Ahmad Hemingway contributed to this report.