MILPITAS ( CBS SF) – Authorities in Milpitas are searching a large park in that city on Sunday for a missing 63-year-old man who is considered at-risk.

Mark Herbert Thornton, of Milpitas, was last seen near Coelho Street in Milpitas, according to police.

The Santa Clara County Sheriff’s Office Search and Rescue team is assisting with the search in Ed R. Levin County Park.

Thornton is described as 5 feet 9 inches tall, 164 pounds with blue eyes, and black and gray hair. He was wearing a red vest, black jeans and gray hiking boots, police said.

Anyone with information about Thornton’s location should call 911.

© Copyright 2019 CBS Broadcasting Inc. and Bay City News Service. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.