Brittany Killgore

An active duty marine arrested on an unrelated charge is being questioned in connection with a 22-year-old Fallbrook, Calif., woman who has been missing since Friday.

Brittany Dawn Killgore was last seen by a friend on Friday in Fallbrook around 5 p.m. Police believe the marine, 45-year-old Louis Ray Perez, was the last person seen with Brittany.

Perez, who is based at Camp Pendleton, was booked at the San Diego Central Jail on an unrelated charge of possession of a stolen AR-15 assault rifle. According to the San Diego Central Jail website, Perez was arrested yesterday and is being held on $500,000 bail.

Killgore was reported missing Saturday evening.

"Due to suspicious circumstances, detectives from the Fallbrook Sheriff's Station and the Homicide Detail were requested and responded," the Sheriff's Department said in a statement.

Police believe there is a "strong likelihood" she is a victim of foul play.

"We recovered her cell phone in the gas lamp district of San Diego," said Lt. Larry Nesbit of the San Diego County Sheriff's department.

Police are not revealing the connection between Killgore and Perez. She was last seen wearing a dark purple evening gown with purple floral glitter patterns. She is a white female, 5-7?, 130 pounds with brown hair and brown eyes, according to the Sheriff's department.

The Sheriff's department is deploying Sheriff's Search and Rescue units to assist in locating the woman. Anyone with information can call Homicide Detail at (858) 974-2321/after hours at (858) 565-5200 or Crime Stoppers at (888) 580-TIPS (8477).