Authorities wrapped up a second day of searching Sunday with no signs of a reportedly despondent Sacramento man who disappeared in Santa Rosa's Annadel State Park.

The 35-year-old man, whose name was not released, vanished inside the park Saturday morning after he was reported trespassing onto private property on Lawndale Road, Sonoma County Sheriff's Lt. Bret Sackett said.

Authorities were able to identify the man after running the license plate on his pickup truck. Sackett said the man has mental health issues and is going through some family difficulties.

The man was described as 6 feet 6 inches tall, with sandy brown hair, and weighing 185 pounds.

A mountain biker reported seeing someone who matched the man's description Saturday at dusk. The man was naked and chanting, the cyclist reported.

Dozens of searchers from three different counties fanned out inside the 5,500-acre park Sunday in hopes of finding the man. They were joined by the sheriff's helicopter, Henry-1, which hovered overhead.

The search was highly visible to the mountain bikers, hikers and others who crowded the park Sunday to enjoy the sunny weather.

A woman who described herself as the missing man's wife held vigil at a command post set up at the Warren-Richardson parking lot. She declined comment.

Sackett said with temperatures dropping again overnight, authorities were concerned for the man's safety, particularly if he was not clothed.

Sackett said the search would resume at daylight today.

You can reach Staff Writer Derek Moore at 521-5336 or On Twitter @deadlinederek.