U.S. Capitol Police lieutenant Mike Byrd, left his Glock 22 in a bathroom

A U.S. Capitol Police lieutenant left his service weapon in a bathroom Monday night and the unattended gun was discovered later by another Capitol Police officer.

After the House adjourned on Monday, Lt. Mike Byrd left his Glock 22 in a bathroom in the Capitol Visitor Center complex, according to sources familiar with the incident. Byrd is the commander of the House Chambers section of the Capitol Police and was on the job Tuesday and Wednesday.

Byrd addressed the incident at Tuesday morning’s officer roll call and, according to sources, told fellow officers that he “will be treated differently” because of his rank as a lieutenant. It was not clear what exactly the lieutenant meant by the comment.

Unlike a gun with a traditional safety, a Glock will fire if the trigger is pulled making the discovery of an unattended gun in the Capitol complex particularly concerning.

Capitol Police said a service weapon was discovered “during a routine security sweep” Monday. Once the weapon was secured, the department began an immediate investigation into the matter, according to Capitol Police spokeswoman Eva Malecki.

“The Department takes these matters very seriously, and has a very thorough process to investigate and review incidents such as these, and holds personnel accountable for their actions,” Malecki said in a statement. “Following the investigation’s conclusion, appropriate actions will be taken in accordance with the Department’s official policies and procedures.”

This is not the first time that a case like this has come to light and under investigation in recent years. In 2015, there were a rash of Capitol Police service weapons left behind in inappropriate places.