The commanding officer of the fast-attack submarine Bremerton was removed from his job this week, Navy officials said on Wednesday night.

Cmdr. Travis Zettel was relieved of his duties on Monday by Capt. Michael Lewis, the commander of Submarine Squadron 19. Lewis lost confidence in Zettel's ability to serve as commanding officer, Navy officials said in a statement.

There is an ongoing investigation into Zettel's relief, said Lt. j. g. Michelle Pelissero, a spokeswoman for Submarine Force, U.S. Pacific Fleet. No additional details about his relief were immediately released.

Zettel took command of Bremerton, the Navy's oldest submarine, in August 2016. He was administratively reassigned following his relief to the staff of Submarine Squadron 19, which is based in Bangor, Washington.

Cmdr. David Kaiser, SUBRON 19's deputy commander, has temporarily replaced Zettel until a permanent leader for the Bremerton is named.

Zettel previously attended the College of Naval Warfare and completed a tour on the staff of the Australian submarine force commander in Western Australia, according to his official bio.

He also served as operations officer for the staff of the commander of Submarine Group Seven in Japan and as strategic weapons officer aboard the ballistic-missile submarine Nebraska Gold.

The Bremerton returned to Hawaii from its final deployment in April. For six months, the nation's longest-serving submarine traveled more than 42,000 nautical miles in some of the world's busiest environments, Master Chief Petty Officer Wade Jacobson, Bremerton's boat chief, said in a Navy news release.

The Bremerton later returned to its namesake city in Washington state where it began its decommissioning process. The submarine had been in service for more than 37 years.

--Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter at @ginaaharkins.