Vallejo's chief of police said he had launched an independent third-party investigation to investigate allegations that officials bent corners of their badges to mark murders.
The investigation follows an investigation that chief Shawny Williams announced earlier this week, which also looks at allegations that the police had involved in the shootings after officials shot him.
"We have received statements from the Vallejo Police Department from two different sources that the badges have been bent," Williams said in a statement. "Because of these very worrying and worrying allegations, I asked that an independent external investigation be carried out by a third party.
The independent investigation will begin next week and will take several months, the authorities said.
The allegations emerged after a long investigation by the online newspaper Open Vallejo.
Former police captain John Whitney said he was seeking corrective action and was released for it. Through his lawyer, he said he learned about the practice of "badge bending" after the fatal shootout of 20-year-old Willie McCoy in a passing taco bell in February 2019. McCoy slept by the window with a pistol in his lap.
McCoy's family lawyer, Melissa Nold, previously said the Vallejo Police Department was a gang.
"That kind of gait culture thing, gashes on your belt that do something to commemorate people, it's gait culture," she said.
In the meantime, the Attorney General has also opened an investigation into allegations of evidence destruction by the Vallejo police that involved shots by officials in the past month that killed Sean Monterrosa.