Drivers enter their location, search radius and required fuel type.

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They have launched an extensive search in a 3-mile radius of the girl's home, where she lives with her parents and two older brothers, as well as contacted all registered sex offenders living nearby.

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Seventeen search teams on Saturday combed a 5-mile radius of the mountain, searching for any signs of Emerson.

CNN: Friends hope for 'miracle' as missing hiker presumed dead