LA CROSSE, WIS. - No one was in custody Sunday in the shooting deaths of a father and son inside a family photography store that left this western Wisconsin town shocked and grieving.

Police and family members identified the victims as store owner Paul Petras, 56, and his son A.J. Petras, 19, according to the La Crosse Tribune.

La Crosse police Capt. Robert Lawrence said the two were killed at about 2 p.m. Saturday, roughly the same time a photography class at May's Photo ends and the store closes.

The crime scene at 425 Main St. and the entire block of Main between 4th and 5th Streets remained blocked Sunday by yellow police tape.

The site "will remain closed until forensic analysis is completed," according to a news release from Lawrence.

The Petrases are believed to have been shot sometime around the store's closing time of 2 p.m. Saturday, although police weren't called to the scene until shortly after 5, when they found that the men had been shot to death, the Tribune reported.

Steve Rose, owner of Rose Jewelers next door to May's, said his son Jon was in the photo store between 1 and 1:30 p.m. Saturday to buy a soda. A.J. waited on him, and everything was OK at the time, Rose said. "We closed at 3," Rose said. "My son left at 3:05 and I left at 3:15. My son said he remarked to himself that it was peculiar that Paul's car was still there. Usually, they were out at 2.

"It's absolutely bizarre, very tragic," Rose said.

Anyone with information is asked to call police at 608-785-5962 or La Crosse Area Crime Stoppers at 608-784-8477. Callers can remain anonymous.

A.J. Petras was a 2011 graduate of Aquinas High School and a member of the school's ski team. On Sunday, friends poured out their shock and grief on his Facebook page, as well as on a remembrance page created in honor of him and his father.

The Associated Press and staff writer Pamela Miller contributed to this report.