Authorities say the 12-year-old knows how to drive, and initially thought the girls took the car out for a ride. Investigators are not calling this case an abduction. Now they believe an adult was likely behind their disappearance.
"It could be a boyfriend, it could be a friend, it could be a birth parent... It could be anything. But we're checking out all possible suspects at this time," said Lt. Michael Rodriguez of the Los Angeles County Sheriff's Department.
The birth father of Robin Lemus, Felicio Lemus, said police searched his Glendale home Monday morning. Lemus says his daughter text messaged him several times last week, complaining about the treatment at the foster home.
"My daughter called and she was crying, because she said the foster mom didn't give her dinner. I called her back around 9:30 and she was crying. I just told her to be patient and to see if she could get some water or something. And she said she was not allowed to get out of her room," said Felicio Lemus.
Authorities believe the girls left the home around 3 a.m., but a neighbor said he saw the girls get into the Lexus hours earlier.
"I saw the 8-year-old, but I wasn't sure the 12-year-old wasn't an adult. I thought she was an adult. So I didn't really think anything of it. I saw them get into the car around midnight," said Nick Patton.
Patton said the girls got into the car through the back passenger side door, as if they were trying not to be seen.
"They were sitting inside the car for about 15 or 20 minutes and started the car up. And I went back inside because I didn't think anything of it," said Patton.
The dark blue Lexus authorities are looking for is a 1998 ES 300. The California license plate number is 3XSR179.
Anyone with information is asked to call the Los Angeles County Sheriff's Department at (909) 450-2711.
Eyewitness News Reporters Gene Gleeson and Robert Holguin contributed to this report.