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(KTLA) — An off-duty Los Angeles County Sheriff’s Department deputy is in critical condition after being shot in the head at a Jack in the Box restaurant in Alhambra Monday, authorities said.

FOX40 sister station KTLA reports the deputy was standing at the counter in the restaurant and wearing civilian clothes when a man armed with a handgun approached him and shot him once in the head. The man then fled at around 6 p.m., sheriff’s department officials said as they stood outside County-USC Medical Center, where the unnamed deputy was hospitalized.

The shooting at the restaurant in the 2000 block of West Valley Boulevard was caught on tape, according to authorities.

The suspected gunman was seen driving away from the scene in a white 2016 Kia four-door SUV with paper plates, the sheriff’s department said.

Surveillance video from a nearby home showed the suspect then stopped the car in an adjacent residential neighborhood and changed into a black T-shirt and jeans before driving away in the same car, officials said.

The gunman was described as a white or Latino man in his 20s. At the time of the shooting, he was wearing a burgundy, button-down, short-sleeved shirt, shorts, sunglasses and a hat.

Aerial video from KTLA’s Sky5 showed officers searching a dumpster outside the restaurant and speaking to people at a home in a nearby residential area, where several police cars were stopped.

Sheriff’s officials said there does not appear to be a clear motive in this case.

Investigators were reviewing forensic evidence and interviewing witnesses at the scene, authorities said.

Officials did not name the deputy, pending notification of his family members.

The investigation is ongoing. No further details were immediately available.

Check back for updates on this developing story.