WESTMINSTER, Colo. (AP) -- Police in Westminster are looking for a 10-year-old girl who was last seen walking to school.

Jessica Ridgeway normally meets a friend at a park on her way to Witt Elementary School, but she didn't make it to the park or school Friday.

Police say they got a late start looking searching because her mother didn't immediately realize she was missing. Officers say the woman works nights and slept through calls from school officials to tell her Jessica hadn't arrived.

An Amber Alert was issued. Searchers included some 50 personnel as well as members of the public, family and friends. Police say a bloodhound and thermal equipment were being used.

Authorities cited a child custody dispute involving her father, but said they don't believe Jessica is with him.