A Marine stationed at Marine Corps Base Hawaii at Kaneohe Bay was pronounced dead Saturday after being found unresponsive in waters off the base.

“The Marine was transported to Adventist Health Castle in Kailua, Hawaii, and was pronounced deceased by medical authorities,” Gunnery Sgt. Orlando Perez, a MCBH spokesperson, said. “Our deepest condolences are with the family and friends of the Marine as we all grieve this tremendous loss. The situation is under investigation and no further details are available at this time.”

First responders pulled the Marine from the water after a 911 caller reported being separated from their free-diving partner offshore of Marine Corps Base Hawaii.

According to the Honolulu Fire Department, firefighters and HFD’s Air 1 helicopter were dispatched after the 911 call at 8:48 a.m.

Honolulu Ocean Safety and Federal Fire Department personnel also responded to the report of a free diver who went missing about 100 yards offshore near Pond Road.

Ocean Safety personnel using a jet ski “retrieved the unresponsive diver from the ocean and brought him to shore,” authorities said.

HFD’s Air 1 transported himto a Federal Fire Department emergency medical unit near North Beach at 10:01 a.m. and he was taken to the hospital where he was pronounced dead.