A 21-year-old airman from Livermore, California, died July 7 while attending the Air Force's Survival, Evasion, Resistance and Escape training, Air Education and Training Command said Tuesday.

Airman 1st Class Kenneth Sturgill of Livermore, California, was found unresponsive by SERE instructors during what AETC called a routine safety check. Military and civilian medical personnel were unable to revive him. In the release, AETC said in a release that Sturgill died on his 18th of 19 days at the SERE Selection School at Joint Base San Antonio-Camp Bullis in Texas.

AETC is still investigating the cause of his death. Sturgill was assigned to the 66th Training Squadron, Detachment 3.

AETC is still investigating the cause of his death. 

"Our thoughts and prayers are with Airman Sturgill's family and friends during this very difficult time," Lt. Col. Clint Rea, commander of the 66th, said in the release. "We will continue to offer them all of our support."

AETC spokesman Capt. Jose Davis said Sturgill recently joined the Air Force, though he was not sure when. Davis said AETC hopes to release additional information on Sturgill's death later this week.

A photograph of Sturgill was not available, Davis said.