SAN MATEO COUNTY — Authorities are searching for a man they say went missing over the weekend near the Peninsula coastline.

Brian Butler, 36, was reported missing Sunday after his friends found his car abandoned off Highway 1 just south of the Tom Lantos Tunnels, said Rebecca Rosenblatt, spokeswoman for the San Mateo County Sheriff’s Office. Friends told investigators that the man had been depressed recently, and are worried he may be suicidal.

Butler was last seen driving in the area in his car, which was found Saturday evening, and has not been heard from since, Rosenblatt said. He is a white male standing about 5-feet-8 inches tall and weighing about 155 pounds. He has brown hair and brown eyes, and was wearing jeans and a blue T-shirt at the time of his disappearance.

Anyone with information about Butler’s whereabouts is asked to contact San Mateo County Detective Lisandro Lopez at 650-363-4055, or the San Mateo County Sheriff’s Office Anonymous Tip Line at 1-800-547-2700.

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.