State finds ‘insufficient evidence’ to charge Vallejo detective who killed Sean Monterrosa

More than three years after the fatal shooting of 22-year-old Sean Monterrosa by a Vallejo police detective spurred demands for an investigation, the California Department of Justice has closed the case without bringing charges.

Announcing the completion of a lengthy probe, state Atty. Gen. Rob Bonta said Tuesday that the department had found insufficient evidence to prove beyond a reasonable doubt that Vallejo Det. Jarrett Tonn did not act in self-defense or defense of his partner when he shot and killed Monterrosa, so criminal charges could not be supported.

However, Bonta said, “Sean Monterrosa’s life mattered, and there is nothing that can make up for his death.”

“His loss is and will continue to be felt by his family and the Bay Area community,” the attorney general added. “It’s critical that these difficult incidents undergo a transparent, fair, and thorough review.”

The fatal shooting outside a Vallejo Walgreens occurred on June 2, 2020, after police said they believed Monterrosa was running from the scene of a burglary and had a gun. Tonn — who arrived in an unmarked truck with two fellow detectives — said he saw Monterrosa grabbing a gun from his waistband, according to the factual summary in the investigation documents.

Tonn fired five shots from his rifle from inside the truck through its windshield, striking Montserrat in the back of the head, according to the documents. The police then found that Monterrossa, a carpenter, was not carrying a gun but a hammer.

The state Department of Justice also investigated whether the Vallejo Police Department had illegally destroyed evidence when it quickly installed a new windshield in the truck and discarded the damaged one. The investigation concluded that the officers involved in the decision to replace the windshield were unrelated to the shooting and did not act with criminal intent.

The state agency said that its investigators and additional experts had thoroughly examined all available evidence — including dispatch records, 911 recordings, surveillance videos, witness and officer interviews and Monterrossa’s autopsy report — before the decision not to file charges was reached.

The Vallejo Police Department placed Tonn on administrative leave after the shooting, and fired him in 2021. The department reversed that decision in August, the San Francisco Chronicle reported, after an arbitrator ruled against his termination.

In the meantime, the state Department of Justice has sought a series of changes within the Vallejo Police Department aimed at reducing its officers’ use of force. According to Bonta, his department and the Vallejo police have agreed on a five-year plan that includes strict limits on officers shooting out of moving vehicles and a requirement that officers try to deescalate situations “when feasible.”

An attorney for the Monterrosa family, which is suing the Vallejo police and Officer Tonn in federal court, could not be reached for comment, nor could a lawyer for Tonn.