[Sweet_Sunflower29]

Does the phone need to be on in order to pinpoint it's position? Just wondering, because that's how the GPS in mine works; may be something similiar even w/out GPS.

Prayers for the missing girl's family...

[SlowBoat407]

The phone is in two-way contact with the nearest tower(s). That's how calls find you no matter where you are.

By finding which towers it's "talking" to, and by reading relative signal strength, authorities can get a fix to within a few blocks of the phone's location. It must be on, though, and have enough juice to maintain the automatic "conversation".