A Los Angeles County sheriff's deputy was shot outside a sheriff's department station Wednesday by someone in a nearby apartment building that houses people being treated for mental illness, authorities said.

Authorities were searching for a possible suspect hours after Deputy Angel Reinosa, 21, a trainee who has been with the department for about a year, was wounded in the shoulder.

Mayor R. Rex Parris said the deputy was wearing a ballistic vest that deflected the bullet into his shoulder.

He was walking to his car outside the Lancaster station just before 3 p.m. when he was struck by gunfire, sheriff's Capt. Todd Weber said. Deputies evacuated him inside to get medical attention.

Reinosa was taken to a hospital with a non-life threatening wound.

Lancaster Mayor R. Rex Parris said the deputy's vest may have saved by deflecting the oncoming bullet into his shoulder.

Investigators believe the shots came from Mental Health America, a four-story building that provides mental health services and housing near the sheriff's station.

Parris raised concerns about having a mentally ill population so close to the sheriff's station.

"It's insanity to allow such a facility to exist in that particular location," he said. "Who decided to put a four-story building that looks down on a parking lot of that particular type there - it's beyond my comprehension," Parris said.

Heavily-armed deputies wearing tactical gear set up a perimeter and launched a massive search for a suspect in triple-digit temperatures.

It's not clear whether the shooter was alone what type of weapon was used. Weber could not say how many rounds were fired or whether deputies fired back.

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The incident came days after a California Highway Patrol officer was gunned down in a shootout in Riverside, a city located 60 miles east of Los Angeles.

Officer Andre Moye, Jr., 34, was filling out paperwork to impound a vehicle when Aaron Luther, 49, allegedly shot him with a rifle. Luther then died in a shootout with law enforcement.