SAN FRANCISCO, Calif. (KRON) — “We need those who tampered with the evidence to be fired and convicted because this is a crime.”

Thursday night, we are hearing from the sisters of Sean Monterrosa — the 22-year-old man who was shot and killed by a Vallejo police officer last month.

The City of Vallejo is now investigating its police department for destroying evidence in the case.

Sean’s family and his attorneys say this is not only inappropriate, but are now trying to figure out how this could’ve happened.

“We are disappointed because it’s a really huge key part in evidence,” Sean’s sisters Ashley and Michelle Monterrosa said.

The Vallejo Police Department is now under investigation for destroying evidence in the Sean Monterrosa case.

The 22-year-old man was shot and killed by a Vallejo police officer last month.

In video released just last week, the officer fired his gun while sitting in the backseat of an unmarked police car.

City officials say the windshield of the Vallejo police car involved in the shooting has been destroyed — a move that disappoints, but doesn’t surprise, the family of the victim.

“It just goes to show they are inept, they’re incompetent,” the sisters said.

City officials also say the vehicle was put back into service despite any consultation with the police chief or the city attorney’s office.

“It would’ve been super crucial and important to keep that piece of evidence and it just goes to prove that the whole Vallejo Police Department and the Vallejo POA is trying to protect this officer and get rid of all the evidence,” Ashley and Michelle Monterrosa said. “But at the end of the day its just making their situation worse.”

The June 2 shooting came after police responded to a Walgreens parking lot following reports of possible looting. police say the officer who shot Sean thought he had a gun.

At the time of the shooting — Sean was kneeling on the ground.

His death sparked a number of protests throughout the Bay Area.

City officials say an employee has been placed on administrative leave while the city retains an outside investigator to investigate the destruction of evidence.

the 18-year veteran officer involved in the shooting has also been placed on leave — and has yet to be identified by police.

“Eventually, justice will be served. Justice is on the way,” Ashley and Michelle Monterrosa said. “It’s just a matter of when. It might not be today. It might not be tomorrow.”

KRON4 reached out to police, city councilors and the mayor Thursday night for comment but have not heard back from any city officials.

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