The U.S. Navy commanding officer at Guantanamo Bay has been relieved of duty and reassigned to headquarters, the Navy announced in a brief statement Wednesday. The Navy Region Southeast commander removed Capt. John R. Nettleton from the remote base “due to loss of confidence in Nettleton’s ability to command,” but declined to elaborate because of an ongoing probe into a mysterious death at the base.

The Naval Criminal Investigative Service is investigating the death of 42-year-old commissary worker Christopher Tur, who was found dead Jan. 10 in Guantanamo Bay waters. Tur had been reported missing a day earlier, Navy Region Southeast spokesman Mike Andrews told the Miami Herald last week. Tur’s widow, Lara, is the director of Fleet and Family Services at the base but it’s unclear whether she worked for Nettleton, Navy spokeswoman Kelly Wirfel told Stars and Stripes last week.

The announcement follows President Barack Obama’s State of the Union address, in which Obama vowed to shutter the detention facility in Cuba, where suspected terrorists have been held for years without charges. Obama has steadily reduced Guantanamo’s prisoner population since he took office. Meanwhile, Senate Republicans have stood against the president’s pledge to close the facility before he departs the White House in two years.

Nettleton has no role in the running of these prison camps, the Miami Herald reported. Navy Rear Adm. Mary M. Jackson, the Navy Region Southeast commander, sent her chief of staff, Capt. Scott Gray, to temporarily run Guantanamo’s naval base until Nettleton’s replacement is selected, according to the Navy statement.