PORTLAND, Ore. (KOIN) — Washington state Sen. Jeff Wilson, a Republican, was arrested at a Hong Kong airport on Oct. 20 for accidentally keeping an unloaded pistol in his carry-on luggage, which initially passed through TSA screenings at Portland International Airport without an issue, the senator announced on the Washington State Senate Republican Caucus website Monday.

The Longview lawmaker said that he mistakenly left the gun inside his carry-on luggage while traveling to Southeast Asia with his wife for a five-week vacation. After taking off from PDX with the gun in his briefcase, Wilson said he found the gun on his connecting flight from SFO to Hong Kong while looking for a piece of gum.

“Wilson said he discovered the weapon mid-flight between San Francisco and Hong Kong when he reached into his briefcase for a piece of gum and felt his unloaded revolver inside,” Wilson’s office said.

Wilson said that he immediately reported the gun to Chinese customs officials after landing in Hong Kong, which resulted in his arrest. Wilson was charged with possession of an unregistered firearm and held in Chinese custody until he posted bail on Sunday. He faces a hearing on Oct. 30.

“It was an honest mistake and I expect the situation to be resolved shortly,” he said.

Wilson said that although his pistol is not registered in Hong Kong, it is properly registered in Washington state, where he holds a concealed carry license. The senator said that he hopes to resolve the issue and resume his vacation.

The Transportation Security Administration told KOIN 6 News that it is actively investigating how the gun made it past its PDX security checkpoint undetected.