TAMPA — About 90 minutes after a 9-year-old boy found a loaded handgun in a movie theater bathroom Sunday, sheriff's Detective Luke Hussey realized he was missing his Glock.

Hussey, 38, who has been with the Hillsborough County Sheriff's Office for 13 years, was off duty that day. He had gone to Muvico Centro Ybor 20, according to the Sheriff's Office, about 3 p.m. and stopped in the bathroom before the movie. He put his Glock 26, a personal weapon, on top of a toilet paper dispenser — then forgot it and left.

Minutes later, Temple Terrace 9-year-old Zane Noland entered the same stall and saw the gun. He exited the stall and told his father, Wesley Noland, 48, who had taken Zane and his older brother, Ryan, to the theater to see Man of Steel on Father's Day.

Wesley Noland, a Marine veteran, went into the stall, disarmed the Glock and called 911.

By the time Hussey realized he'd lost his gun, Tampa police had taken it. He called Sunday and asked for it back, police said, but was told only a detective in the firearms unit could release it.

The Sheriff's Office announced Tuesday that Hussey is the subject of an administrative investigation that could result in suspension or termination.

"It's obviously a serious mistake," said sheriff's spokesman Larry McKinnon. "We're glad no one was hurt, that the gun didn't end up in the wrong hands."

He was unsure if Hussey had prior disciplinary issues and his personnel file was unavailable for review Tuesday night. He remains on active duty.

Hussey will not face criminal charges, Tampa police said Tuesday. A day earlier, when news of the boy's discovery broke, police spokeswoman Laura McElroy mentioned possible charges of reckless endangerment or culpable negligence against the gun's owner, whom she said police were still looking for at the time.

"It was always our goal to ensure the person who left the gun face consequences," McElroy said Tuesday. "There is no doubt that will happen within his organization."

Wesley Noland said he was disappointed to learn a law enforcement officer was responsible.

"He's taken an oath of office to protect the public, and he left a loaded firearm in a bathroom in a movie theater full of kids," he said. "I'm shocked and saddened."

Hussey's case of absent-mindedness with a gun is not uncommon, even among law enforcement officers. In 2005, a Virginia officer left her gun in an airport bathroom. In 2007, a Philadelphia officer left his on a boardwalk amusement ride, where it was picked up by a teenage girl. No one was hurt. In April, a deputy for the Norfolk, Va., Sheriff's Office left his gun in the dressing room of a Macy's. None of those officers faced criminal charges, according to news reports.

The commonness of the incident is no consolation to Noland.

But he was puzzled Tuesday about one thing: Why, if Hussey had called Tampa police on Sunday to claim his gun, did police officials say Monday night they were still looking for the owner?

Police spokeswoman McElroy said detectives with the firearms unit came in Monday and worked on cases they already had open. They didn't get to this report until Tuesday — and as soon as they did, they realized they could call off the search for the gun's owner.

"He's devastated about it," sheriff's spokesman McKinnon said of Hussey. "In all my years, I don't remember a case like this one. But one is too many."

Times researcher Caryn Baird contributed to this report. Will Hobson can be reached at (813) 226-3400 or whobson@tampabay.com.