The police chief of a San Francisco Bay Area city under scrutiny after several fatal police shootings said he is opening an inquiry into allegations that officers bent their badges to mark on-duty killings.

Vallejo Police Chief Shawny Williams told the San Francisco Chronicle on Wednesday that he would not tolerate such a “despicable” act if the claims are true.

John Whitney, a former Vallejo police captain, previously accused the department of firing him in August for flagging misconduct that included concerns that some officers bent their badges in a ritual to mark fatal shootings.

Whitney shared his concerns with several top city officials, including Mayor Bob Sampayan, before he was let go, his lawyer told the Chronicle.

The Police Department is separately under investigation for the destruction of evidence in the fatal shooting this June of a looting suspect who officers mistakenly thought had a gun.

In that case, city officials asked the FBI and state Attorney General’s Office to investigate after they say they discovered police destroyed the windshield of the police vehicle involved in 22-year-old Sean Monterrosa’s death.