Updated 02/13/14 – 11:11 a.m.

CHICAGO (CBS) — Five people, including the gunman, were shot during an apparent robbery attempt at a social club for seniors in Gary, Ind.

It was anything but safe Wednesday night for patrons at the Safe and Sound Senior Citizen Social Club. Police said, around 11:30 p.m., a 23-year-old man walked into the club, brandishing a gun, and told everyone to get down on the floor.

“When he came in, he … told everybody to get on the floor, and he had a gun. He was armed with a weapon, so that sounds like the fruits of a robbery,” said Gary Police Cpl. Gabrielle King.

By the time police arrived, the robber had shot four men; ages 76, 65, 45, and 43. King said it’s unclear why the robber began shooting.

“It’s still too early in the investigation to tell,” she said.

The suspect also was shot during the robbery attempt.

“It’s unknown who shot him. Apparently, someone from inside of the club,” King said, adding it was possible he accidentally shot himself.

The four men he shot were taken to Methodist Hospitals Northlake Campus. The hospital said three of the men were still at the hospital Thursday morning, in stable condition. A fourth had been airlifted to Loyola University Medical Center in Maywood, in critical condition.

The gunman also was treated at Methodist, but was discharged into police custody.

More than two years ago, the club was raided for serving alcohol without a license, and for gambling activity.