SAN DIEGO -  

Authorities Saturday were seeking the public's help in locating an 18-year-old man who was last seen near a high school in southeastern San Diego.

Robert Nathaniel Manalo was last seen around 7:30 a.m. on Tuesday near Morse High School, according to San Diego police.

Manalo's 2002 Toyota pickup truck was found abandoned in San Juan Capistrano in Orange County in the area of Avenida Aeropuerto and Calle Aviador, police said.

Manalo, who San Diego police described as having been depressed recently, is Asian and 5 feet 9 inches tall. He weighs about 150 pounds and has black hair and brown eyes. He was wearing a black The North Face jacket, blue jeans and a black baseball cap.

Anyone with information about Manalo's whereabouts was urged to call San Diego police at (619) 531-2000 or San Diego police Detective Mo Parga at (619) 972-2734.