Erin Corwin, 19, was last seen June 29 when she left home to travel to Joshua Tree National Park.
According to the Military Times, police have found Corwin's 2013 Toyota Corrolla and deem her disappearance suspicious enough to have deployed homicide detectives in the case.
"The specialized division was asked to assume the investigation because they felt that there were definite suspicious circumstances," San Bernardino County sheriff's spokeswoman Cindy Bachman told reporters.
Corwin is three months pregnant. She and her husband, Marine Cpl. Jonathan Corwin, are from Oak Ridge, Tennessee, and live at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif.
The missing woman's family flew in from Tennessee upon hearing of their daughter's disappearance. Lore Heavilin, Erin Corwin's mother, said she had been planning to visit her daughter and that the reason she was headed to Joshua Tree National Park was to check it out as a possible spot they could go together.
"I mean, she was so excited about that upcoming trip. The things we were going to do," Heavilin told the station.