VALLEJO (KPIX) — An independent investigation into the 2020 police shooting death of Sean Monterrosa concluded that the use of deadly force by a Vallejo officer was not “objectively reasonable.”

For Monterrosa’s family, this is just one step in seeking justice for their loved one.

On June 2, 2020, Vallejo police responded to a looting call at a Walgreens. Monterrosa was shot by an officer who mistakenly thought a hammer he had in his pocket was a gun.

Since the incident, several investigations have been initiated, including an independent review.

Officers at the scene were interviewed with one recalling, “You hear on the radio ‘I think they’re armed.’ Then you heard pop pop pop.”

The investigation relied heavily on interviews with the officers and on body-cam footage of the incident. Vallejo police also released portions of the interviews they conducted.

One officer remembered the night this way: “Kind of an emotional night, it looks like the car started taking off and I think he thought he was being left so he turned back towards the cops at that point.”

The review not only concluded the shooting was not “objectively reasonable” but investigators said Monterrosa’s perceived threatening behavior was predicated on the tactically-poor way the officers responded and on their failure to deploy any de-escalation techniques.

Vallejo police chief Shawny Williams said these findings are the first steps to discipline the officer and he wants to be open, fair and transparent throughout the process.

The criminal investigation is currently being conducted by the California Attorney General’s office.