SACRAMENTO, Calif. (AP) — Hundreds of volunteers on Sunday were taking part in a search along the American River in Sacramento for a missing University of California, Davis student.

The search for Linnea Lomax comes as Marc Klaas, who founded the KlaasKids Foundation after his 12-year-old daughter was kidnapped from her Petaluma home and murdered in 1993, said he was getting involved in the efforts to find her.

The 19-year-old Lomax, a student at the University of California, Davis, has been missing since she walked away from an outpatient mental health facility in Sacramento on June 26.

Her family said she was getting treatment at the facility. Officials say she has not been seen since she left the facility.

(Copyright 2012 The Associated Press.)