Police search Colorado suburb for missing 10-year-old Jessica Ridgeway, who disappeared on walk to school

This image provided by the Westminster Police Department shows 10-year-old Jessica Ridgeway. Police in Westminster are looking for the girl, who was last seen walking to school.

WESTMINSTER, Colo. - A search is under way in a Denver suburb for a 10-year-old girl who was last seen walking to school Friday morning.

Jessica Ridgeway normally meets classmates at a park where they walk to Witt Elementary School, but she didn't make it to the park or school, Westminster police said.

Authorities got a late start searching because her mother didn't immediately realize she was missing, police said in a news release. Her mother works nights and slept through a call from school officials to tell her Jessica hadn't arrived.

Police said an Amber Alert was issued Friday evening after investigators determined they had a reasonable suspicion that an abduction took place.

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

Some 50 personnel were searching trails, parks and open spaces in the surrounding area. They were also going door to door as well as using search dogs and thermal equipment. Police said members of the public, family and friends were also searching.

Police said they have made reverse phone calls to more than 12,000 homes in the area, while Jefferson County School District called more than 400 families of students and faculty members.

Jessica has blue eyes and blond hair to her shoulders, and is 4-feet-10 and weighs 80 pounds. She was wearing a black jacket and pink and purple colored glasses.