(RACINE, Wisc.) -- A reward to help catch the gunman who killed an off-duty Wisconsin police officer has climbed to $37,000 .
Officer John Hetland, a 24-year veteran of the Racine Police Department, was at Teezers Tavern in Racine Monday night when he saw an armed robbery unfolding, police said. He tried to intervene and was shot, police said.
As authorities continue to search for his killer, Racine Police Chief Art Howell said Thursday that a local business has provided a $15,000 reward.
The FBI has already offered a $20,000 reward, while Racine Crime Stoppers has provided a $2,000 reward, the chief said.
Though tips have been pouring in, Kenosha County Sheriff David Beth said he hopes the large reward convinces more people to come forward.
"Help us catch this person and get him off the streets," Beth urged at a news conference Thursday.
Meanwhile, the shocking slaying has been "extremely traumatic" for Howell's fellow officers, Howell said.
But the chief added, "they are a resilient group of people. They are bruised but they are not broken."
"They are doing what John would want them to do," he said. "They are serving the public."
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 Hetland before his death. "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."
Hetland will be laid to rest on June 26, the chief said.
Copyright © 2019, ABC Radio. All rights reserved.