COLUMBIA, S.C., Aug. 26 (UPI) -- The FBI has joined the search for a missing South Carolina teenager who disappeared a week ago, officials said.
Gabrielle Swainson, 15, vanished from her Richland County home near Columbia between the hours of 3:30 a.m. and 7:30 a.m. on Aug. 18, while her mother was at work, ABC News reported.
When her mother, Elvia Swainson, returned home later that morning, Gabrielle was no where to be found.
"I grabbed my phone and started calling her number. The number rang a couple of times then it stopped," Swainson said.
The mother said further attempts to reach her daughter were unsuccessful.
"I don't know what has happened. I don't know how it happened and this is really a nightmare. It really is," Elvia Swainson said. "It's the worst situation a parent could be in."
Investigators said although there are no signs of foul play, it is not likely that the teenager left home of her own free will.
"Her purse was still there with her charger for her phone in it and all the ingredients of her purse like her wallet and her credit card, everything is still there," said Chandra Cleveland-Jennings, a private investigator hired by Swainson.