Sitting at home, in your office, or even in driving in your car, your cellphone is sending signals that can locate your general area, and some your exact position.
Police investigations use the technology to search for missing persons such as Brittanee Drexel and lately for Kristy Thornbrew, 29, of Florence who has been missing since Monday in the mountains of western North Carolina.
Friends say Thornbrew left a cabin to see the sunrise from a mountaintop near Bat Cave.
Buncombe County Sheriff Lt. Randy Sorrells is leading the investigation into Thornbrew's disappearance and says there is no indication of foul play at this time.
The North Carolina Bureau of Investigation is processing the scene.
Thornbrew's boyfriend, Mark Carmichael, says Thornbrew missed a ride back to Florence after she went to North Carolina for a concert. Carmichael did not attend the concert. He was in Charleston at the time.
Sorrells says investigators are using every possible technology available. "We definitely know she made a call to a friend around 9 a.m. the morning she went missing," says Sorrells. "We've used the cellphone as a tool to help us."
Sorrells wouldn't go into detail about how they track locations using cell phone.
But Horry County Telephone Cooperative, or HTC, main engineer Ryan Graham says the only time police or detectives can pinpoint an exact location is when the person dials 911. "After September 11th, the FCC (Federal Communications Commission) mandated that we pinpoint callers who dial 911," says Graham "but when you make any other phone call not to 911, we can not triangulate the exact location of the position."
All of HTC's cell phone information is sent directly to its server in Columbia. Those signals can only give an approximate area of a person's location when they make a call. "We could tell what time a phone call happened, the sector where it started and finished," Graham says.
Some newer phones like the iPhone and some BlackBerry phones have assisted GPS to find an exact location. "With these phones, we can find exactly where a phone is if it's sending out that GPS signal," says Graham.
Thornbrew's phone does not have GPS.
Sorrells says they are searching the area with dogs, about 50 to 60 people, and a helicopter to locate Thornbrew. "It's good weather today," he says. "Hopefully something will turn up, and we'll have a good day."
The Assocaited Press contributed to this story.
