Louis Ray Perez, 45, was arrested on suspicion of murder. Perez, who is also a Camp Pendleton Marine, had been a person of interest since the disappearance and murder of Brittany Killgore.
He has been in police custody since April 14 on charges of possessing a stolen weapon. Police believe he was the last person seen with Brittany Killgore.
Brittany Killgore's body was found naked and dumped near Lake Skinner in Riverside County, about 25 miles from her apartment in Fallbrook.
Investigators say a suicide note written by Jessica Lynn Lopez told them where to find the body. The 25-year-old has pleaded not guilty to murder charges
Prosecutors remain tight-lipped about a possible motive, and authorities aren't saying how Perez or Lopez are connected to the case.
Brittany Killgore disappeared four days after she filed for divorce from her husband, Lance Cpl. Cory Killgore, who has been serving a tour of duty in Afghanistan. He is returning to Southern California on emergency leave due to the investigation. Authorities say he is not a suspect.