CHICAGO (Reuters) - A federal air marshal accidentally left her gun in a restroom beyond the security checkpoints at Cleveland Hopkins International Airport, officials say.

The weapon was discovered by a passenger who alerted an airline employee.

The marshal remained on the job after Thursday’s incident when she visited an airport restroom and inadvertently left her gun behind, Dave Adams, spokesman for the Federal Air Marshal Service in Washington, said Saturday.

The restroom was beyond security checkpoints, airport spokeswoman Pat Smith said. So the risk was that someone could have discovered the gun and taken it on a flight.

“Right now we’re still doing the investigation,” Adams said. “It will determine what disciplinary action will be appropriate.”

He declined to identify the marshal for security reasons, but said her work in the past had been “outstanding.”

The United States deploys armed air marshals disguised as passengers on thousands of flights each week as part of security measures implemented after the Sept. 11, 2001, hijacked airliner attacks that killed about 3,000 people.

Smith said the incident occurred about 4 p.m. on Thursday when the air marshal went to the restroom. While washing her hands, she placed her gun on a shelf, but forgot to take it with her when she left the room.

Soon afterward, a passenger found the gun and informed an airline employee, who removed it and told police. The gun later was returned to the marshal.

Reuters 2004. All Rights Reserved.

Mon Apr 12, 2004 10:35 AM ET