LA CROSSE, Wis. (WCCO) — La Crosse, Wis., police are asking the public’s help in finding a gunman who killed a father and son inside their family business on Saturday.

The victims, identified by family as 56-year-old Paul Petras and his 19-year-old son, A.J. (pictured below), were shot to death at May’s Photo in downtown La Crosse at approximately 2 p.m. Saturday. It was around the same time a weekend photography class was ending, investigators said.

“When I got the call, it was really gut wrenching,” Capt. Robert Lawrence told CBS affiliate News8 in La Crosse. “It was something that really took me back that we have another homicide that we are investigating.”

(credit: AJ Petras’ Facebook Page)

The Department of Criminal Investigation is sending a team to La Crosse, Wis., to help with the investigation.

Police have not released any information on a possible suspect. Anyone with information is encouraged to call the La Crosse Police Department at (608) 785-5962.

“It’s imperative for the community to let us know anything (suspicious) that they saw,” Lawrence said.

According to newspaper archives, Paul Petras ran May’s Photo, a business started by his father. They formerly had a store in Winona, Minn.