A San Carlos man was sentenced Wednesday to 25 years in federal prison for the slaying of a security guard.

Federal prosecutors say 23-year-old Melvin Pascal Nash previously pleaded guilty to second-degree murder, as did co-defendant Mason James Henry.

Authorities say 30-year-old Aaron Anthony Tierno, of Phoenix, was fatally shot near San Carlos Lake on the San Carlos Apache Indian Reservation on Aug. 28, 2008.

They say Tierno, an Iraq war veteran, had been temporarily in the area working as a security guard for a construction project and had no prior association with either Nash or Henry.

The 20-year-old Henry, also of San Carlos, is scheduled to be sentenced Dec. 22.