Los Angeles: A Los Angeles County deputy who sparked a manhunt when he said he was shot in the shoulder by a sniper lied about the shooting and will face a criminal investigation, authorities say.

"The reported sniper assault was fabricated" by Deputy Angel Reinosa, Assistant Sheriff Robin Limon said at a news conference late Saturday, local time.

A sheriff's department helicopter with a sniper in an open door search for what they thought was a gunman at large in Lancaster, California. Credit:AP

Reinosa, 21, made a frantic radio call Wednesday claiming he'd been shot by someone in a nearby building as he walked to his car outside the Lancaster sheriff's station, prompting a huge police response. Deputies set up a perimeter and SWAT officers went door-to-door inside a sprawling building complex to search for the shooter.

At the time, investigators believed Reinosa's bulletproof vest saved his life but that a bullet grazed him. A department statement the next day said a single round hit the top of Reinosa's shoulder, damaging his uniform shirt but failing to penetrate his flesh.