By Rich McKay

(Reuters) - A Los Angeles County sheriff's deputy has been shot and killed in what officials call an ambush while he was sitting in his patrol car outside a sheriff's station in the California city of Palmdale, in uniform and on duty.

Sheriff Robert Luna called the incident that occurred on Saturday night "murder" and a "targeted attack" on Deputy Ryan Clinkunbroomer, 30, because he was a police officer, serving his community about 55 miles (90 km) northeast of Los Angeles.

Clinkunbroomer was found at the wheel of his patrol cruiser gravely wounded about 6 p.m. by a passerby who called for help, police said. Clinkunbroomer, who served for eight years on the force, died at the hospital.

During a late-night news conference, Luna asked the public to come forward with any video that may exist showing what happened.

Clinkunbroomer, who was just engaged to be married, was a third-generation member of law enforcement, following in the footsteps of his father and grandfather, the sheriff wrote on social media.

"It hurts, it hurts bad," Luna said. "He was murdered (Saturday night). He didn't deserve that. ... From everything I know about Ryan, people loved and adored him."

"We're going to catch this person," he added.

There have been 83 ambush-style attacks on police in the United States this year, resulting in 15 killed by gunfire, according to National Fraternal Order of Police.