SAN DIEGO (CNS) - Volunteer drone enthusiasts lent their services Wednesday to ongoing efforts to locate an Alzheimer's patient from Scripps Ranch who has been missing for nearly a week.

Operators of the camera-equipped flying machines were scanning open areas around the home of 85-year-old Taiheng Sun, who disappeared last Thursday, according to the Scripps Ranch Civic Association.

A surveillance camera captured images of Sun walking to the east on Stonebridge Parkway about 8:30 that morning. He was clad in black pants, a blue long-sleeved shirt, white shoes and a blue baseball hat, and was carrying a white jacket.

Police also released video of a person, possibly Sun, being dropped off about 3 p.m. Saturday in the 11000 block of Legacy Canyon Place by someone driving a beige 2012-2013 Ford Taurus, according to San Diego police Lt. Mike Holden.

The person who gets dropped off lingers in the area for at least 30 minutes before the sun's reflection obscures the camera's view, Holden said.

Relatives of the Maple Grove Lane resident told authorities he had been depressed recently and had expressed suicidal thoughts. He does not drive or have access to other transportation, and knows no one in his neighborhood outside of his family, they said.

Sun is described as a 5-foot-6-inch, roughly 140-pound Asian with gray hair and brown eyes. He speaks very little English, according to San Diego police.

Volunteers can sign up to help in the search for Sun via a Facebook page.

Anyone with information on Sun's whereabouts was asked to call police at (619) 531-2000.