The pilot of an F-15C that crashed on Monday in the North Sea has been found dead, Col. William L. Marshall, commander of the 48th Fighter Wing, has announced.

“It is with a very heavy heart that I confirm the pilot of the downed F-15C Eagle has been located and confirmed deceased,” Marshall said in a brief video. “Out of respect for the family and their privacy during this incredibly difficult time, we will not release the name of the pilot until all next of kin notifications have been completed.”

“This is a tragic loss for the 48th Fighter Wing community,” Marshall continued. “And our deepest condolences go out to the pilot’s family and the 493rd Fighter Squadron.”

The cause of the crash is under investigation, a 48th Fighter Wing news release says.

The plane was based at RAF Lakenheath in the United Kingdom, the release says. It went down about 9:40 a.m. local time during a training mission.

One pilot was on board the fighter at the time of the crash.

The British coast guard found the aircraft's wreckage earlier on Monday.