Washington (CNN) U.S. Capitol Police officers assigned to the security details of the top two Republicans in Congress mistakenly left their Glock pistols in bathroom stalls in two separate recent incidents, according to a congressional source familiar with an internal investigation into the embarrassing mishaps.

In a similar case, a housekeeper working in the Capitol Police headquarters, a few blocks from the Capitol, found another misplaced gun while cleaning, the source said.

CQ/Roll Call first reported the lost guns, citing an investigative report it had obtained about the incidents that was turned over to the U.S. Capitol Police Board, which oversees the U.S. Capitol Police Department. CQ/Roll Call included a photograph of a Glock and its ammunition magazine stuffed into a toilet seat cover holder in a bathroom stall.

The first incident took place in January when a worker in the Congressional Visitors' Center found a Glock jammed into the holder. The gun belonged to a member of Senate Majority Leader Mitch McConnell's security detail, the congressional source said.

The second incident happened in March, when a member of House Speaker John Boehner's police detail left a gun after using a toilet in the speaker's suite of offices in the Capitol. The gun, which CQ/Roll said was loaded, was found by a young child, two congressional sources told CNN. The misplaced gun in the police headquarters was discovered in April, the congressional source said.