The girl, Shelby Harris, was last seen by friends and family on Halloween day at Amador Valley High School. She told her parents that she would return home at the end of the school day.
Harris is white, 5 foot 7 inches and approximately 140 pounds with black hair and brown eyes. She was last seen wearing a Halloween costume consisting of a red cape, red shirt, blue jeans, black high heels, and a Mardi Gras mask.
A police investigation has determined Harris is most likely in the company of Gavin McFate, 25, who is wanted on an Alameda County felony arrest warrant. McFate is a white male, 6 foot 3 inches, approximately 210 pounds with brown hair and brown eyes.
McFate and Harris were last seen in the Concord area on the morning of Nov. 1. They may be in a black late '90s model Honda Accord or Civic.
As of press time Wednesday police were urging anyone with information that may aid in the ongoing investigation and the recovery of Harris to contact them at 931-5100.