SAN DIEGO -- Authorities released the name Tuesday of a 21-year-old Navy man killed in a weekend motorcycle crash in the East County highlands.

Petty Officer Michael Kaske was riding on State Route 78 near Inaja Memorial Park in the Santa Ysabel area when he lost control of his motorcycle for unknown reasons shortly before 3:30 p.m. Sunday, according to the California Highway Patrol and the San Diego County Medical Examiner's Office.

The two-wheeler veered off the roadway and hit a tree, the CHP reported. Emergency crews arrived to find Kaske, a San Diego resident who was serving aboard the USS Higgins, conscious and alert, officials said.

As they assessed his condition, however, Kaske suddenly stopped breathing and passed out. Medics airlifted him to Palomar Medical Center in Escondido, where he was pronounced dead about three hours later.

An autopsy determined that Kaske died of blunt-force head and chest injuries, according to the Medical Examiner's Office.