LOS ANGELES (AP) — The parents of a Los Angeles County deputy who was shot and killed while sitting in his patrol car plan to file a lawsuit accusing the sheriff’s department and county leaders of putting law enforcement officers at risk by making them work excessive overtime because of severe understaffing, an attorney announced Tuesday.

Investigators said Deputy Ryan Clinkunbroomer, 30, was ambushed Sept. 16 while waiting for a traffic light to change in Palmdale, a city of more than 167,000 residents in the high desert of northern LA County.

Clinkunbroomer had racked up 69 hours of overtime in the two weeks leading up to the shooting and had worked a double shift the day before, said attorney Brad Gage, who represents Clinkunbroomer’s parents. The deputy was so exhausted from being overworked that his senses were dulled and he missed “the telltale signs” of an impending ambush, Gage said.

Prosecutors have charged Kevin Cataneo Salazar, 29, with one count of murder, plus special circumstance allegations of murder of a peace officer, murder committed by lying in wait, murder committed by firing from a car and personal use of a firearm. Cataneo Salazar has pleaded not guilty by reason of insanity.

Gage said in a government claim filed Monday that Clinkunbroomer was forced to work more than 100 hours of overtime each month. Gage accuses Sheriff Robert Luna, department officials and county leaders of knowingly endangering the lives of law enforcement officers by enforcing excessive amounts of mandatory overtime.

The claim is the precursor to a wrongful death lawsuit and names the county sheriff’s department and Board of Supervisors. County officials have 45 days to respond to the claim before a lawsuit can be filed.

Gage said the lawsuit would seek $20 million in damages and changes to sheriff’s department staffing and scheduling policies.

In a statement Tuesday, the sheriff’s department did not comment on the potential lawsuit. Luna, who was sworn in as sheriff a year ago, has previously vowed to make increasing the number of sworn deputies a priority.

“The senseless ambush murder of Deputy Ryan Clinkunbroomer was the epitome of evil and the Department continues to mourn his death. We lost a valued member of our Department family who was committed to serving our communities,” the statement said. “The Sheriff’s Department remains committed to securing a successful prosecution against the individual responsible for Ryan’s murder. Our thoughts continue to remain with the entire Clinkunbroomer family.”

Law enforcement officers and members of the public are at risk because “fatigue resulting from these demanding work schedules impairs the deputies’ ability to stay alert and respond effectively in the line of duty,” the claim states.

“Sheriff Luna and the Board of Supervisors knew of the dangers to their employees as a result of intentionally forcing overtime, but intentionally pursued such actions in conscious disregard of the rights and safety of deputies,” Gage writes in the claim.

The Board of Supervisors did not immediately respond to emails seeking comment on the allegations.

“Everybody likes to work a bit of overtime, to earn a bit of extra money, but they don’t want to work so much overtime that they’re unable to take care of themselves and others,” said Gage, the family’s attorney.

The head of the deputies’ union said limited staffing is an ongoing problem, but did not respond to specific questions about average overtime worked by deputies.

“The department’s staffing crisis is pushing our deputies to, and sadly sometimes beyond, their limits. We need our elected officials to take a more aggressive and intelligent approach to addressing the department’s inability to recruit and retain qualified people,” said a statement from Rich Pippin, president of the Association for Los Angeles Deputy Sheriffs. “Failure to do so can only result in more tragic outcomes, not only for our deputy sheriffs, but for the millions of people who rely on them for protection.”

Prosecutors haven’t laid out a motive in the criminal case or said whether Clinkunbroomer and Cataneo Salazar previously knew each other.

Authorities said the deputy was “targeted” but would not say whether Cataneo Salazar was seeking to harm Clinkunbroomer specifically or any member of law enforcement generally.

Cataneo Salazar allegedly followed Clinkunbroomer just before 6 p.m. as he left the sheriff’s Palmdale Station, the district attorney’s office said in a September news release.

The deputy was “waiting for a red light to turn” when he was shot, Luna said at the time.

Cataneo Salazar was arrested after an hourslong standoff with sheriff’s deputies. He had barricaded himself inside his family’s Palmdale home.

His mother, Marle Salazar, told the Los Angeles Times her son was diagnosed as paranoid schizophrenic about five years ago. He would say he was hearing voices in his head, she said, and sometimes claimed that cars or people were following him. He twice attempted suicide and had been hospitalized at least once, she said.