Aug. 25, 2012 -- The FBI has joined the search for a South Carolina cheerleader who vanished without a trace from her bedroom.
Gabrielle Swainson, 15, disappeared between 3:30 a.m. and 7:30 a.m. last Saturday, during the time her mother was at work, police said.
When mother Elvia Swainson returned home Saturday morning, Gabrielle's bed was empty.
"I grabbed my phone and started calling her number. The number rang a couple of times then it stopped," Swainson said.
Several more attempts to reach her daughter went straight to voicemail, she said.
Although there were no signs of foul play, investigators believe the teen's disappearance was not voluntary.
"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.
Cleveland-Jennings said there has been no activity on the teen's phone since her disappearance. Police have not said whether they have been able to locate a signal.
Gabrielle missed the first day of her sophomore year of high school on Thursday at Ridge View High School, where she had just made the junior varsity cheerleading squad.
"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."