Investigators believe she and her husband, private first class George Kevyn Reid, ran off from their posts at Camp Pendleton and Miramar Marine Corp Air Station.
They were reportedly set to be deployed to Iraq in a couple of months.
Lance Corporal Margaret McMahon was last seen on Monday. McMahon, who is newlywed, was at Camp Pendleton doing paperwork to officially change her last name when she vanished without a trace.
The newlyweds, McMahon and Private First-Class George Kevlyn Reid, have been missing since Monday. McMahon has 11 brothers and sisters. Her father is a former Sag Harbor police officer. The strong military family is weak with grief.
Authorities say the two did leave behind some personal belongings, including their uniforms.
