SANTA ANA, Calif. (AP) — Orange County sheriff's officials say a 21-year-old Marine and Iraq war veteran from Camp Pendleton has been arrested for investigation of murder in the slaying of a fellow Marine.

Authorities say a second Marine remains at large and is considered armed and dangerous.

Sheriff's spokesman Jim Amormino says 21-year-old Christian Carney was taken into custody Friday.

Authorities are seeking 20-year-old Alvin Reed Lovely, who is also stationed at Camp Pendleton.

No motive was given for the slaying of 21-year-old Stephen Serrano, whose body was found in a ditch in San Clemente on May 15. He was shot in the chest.