Hours later, dozens of 911 calls flooded the Police Department. Callers reported shots fired inside the apartment building at 4:30 a.m. Saturday. They said they heard glass breaking and someone banging on doors.

As authorities helped dozens from the building, officers and SWAT members contained the shooter as he repeatedly fired an AK-47 rifle. At 5:33 a.m., an officer shot him. He was disarmed and taken to the hospital.

The suspect’s motive is unclear, but police said he was heavily armed. They recovered a shotgun, an AK-47, a .45-caliber handgun and a backpack filled with ammo. O’Hara said the man wore a military-style flak jacket, body armor that holds bullets while protecting its user from gunfire.

“We had the bomb squad come out to check the backpack because I was concerned it could be a boobytrap for first responders,” O’Hara said at the news conference.

Brad Nelson, the owner of Level 10 Management, the company that manages the 24-unit apartment building, said residents were allowed to return later Saturday.

He said he wasn’t aware of any previous calls to law enforcement in connection with the suspect and that property management is waiting to learn more about what happened from the police.