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Killing of Sean Monterrosa

ONGOING2020Walgreens parking lot area, Vallejo, California3 SOURCESUPDATED JUL 2026

Documents violence · ongoing investigation — written to inform, not to shock.

Illustrative

Sean Monterrosa was a 22-year-old man of Argentinean and Salvadoran descent who grew up in San Francisco, attended an arts high school, and had worked for a Boys & Girls Club and as a carpenter. Less than an hour before he was killed, he texted his sister a petition demanding justice for George Floyd. He was killed at 12:30 a.m. on June 2, 2020, in Vallejo, California, while the city was under curfew due to looting. Police were responding to a reported looting at a Walgreens; after a car chase in which a fleeing vehicle rammed and injured an officer, three detectives arrived at the scene in an unmarked pickup truck. Detective Jarrett Tonn, seated in the back, fired a rifle five times through the truck's windshield, striking Monterrosa in the back of the head. Monterrosa was on his knees with his hands above his waist at the time. No firearm was found; police said officers mistook the end of a hammer protruding from his sweatshirt pocket for a gun. Monterrosa later died at a local hospital.

Jarrett Tonn had been a Vallejo police officer since 2014, previously working for the Galt Police Department. Monterrosa's killing marked the fourth time in five years Tonn had shot at someone while on duty; none of the three prior shootings were fatal, and Tonn was cleared of wrongdoing in internal investigations each time. Vallejo police had shot 32 people and killed 18 over the prior decade without any officer being fired for a shooting, and the department had the highest per-capita rate of police shootings in Northern California as of May 2019.

Police delayed disclosing Monterrosa's death for over a day and gave shifting accounts of the incident, including conflicting statements about whether Monterrosa "pointed" a gun. Body camera footage, released weeks later, did not show Monterrosa before the shooting but captured Tonn firing before his vehicle fully stopped and making statements afterward questioning what Monterrosa had "pointed." The windshield through which Tonn fired was later destroyed without authorization by a city employee, prompting a separate California Department of Justice investigation into the destruction of evidence; Vallejo police officer Michael Nichelini was later fired in connection with this, though an arbitrator overturned his termination in December 2022.

In 2022, an independent investigation found Tonn had violated department policies, including unreasonable use of deadly force and failure to activate his body camera, leading to his firing. In August 2023, an arbitration decision reinstated Tonn with back pay, finding his use of force legally justified under California law and finding procedural flaws in the earlier investigation. The Monterrosa family filed a federal civil rights lawsuit against the city of Vallejo and Tonn in August 2020, alleging unjustified use of deadly force. The case prompted sustained protests in Vallejo, San Francisco, and Sacramento calling for accountability and the appointment of a special prosecutor.

Key facts

Victims
Sean Monterrosa
Date
2020
Location
Walgreens parking lot area, Vallejo, California
Case status
ongoing

Case timeline

  1. 2020-06-02

    Sean Monterrosa is shot by Vallejo police detective Jarrett Tonn at approximately 12:30 a.m. and later dies at a hospital.

  2. 2020-06-03

    Vallejo police chief Shawny Williams publicly confirms the officer-involved shooting was fatal.

  3. 2020-06-05

    Bay Area News Group identifies Jarrett Tonn as the shooting officer; police chief gives account of the incident at a press conference.

  4. 2020-06-16

    San Francisco Board of Supervisors passes a resolution urging release of body camera footage; body camera footage is later released.

  5. 2020-06-19

    Sean Monterrosa is laid to rest.

  6. 2020-07-02

    Solano County District Attorney Krishna Abrams recuses herself from the investigation.

  7. 2020-07-15

    Vallejo city manager's office announces the windshield evidence was destroyed without permission.

  8. 2020-07-17

    California Attorney General Xavier Becerra announces an investigation into the destruction of evidence; Nancy Pelosi calls for an FBI investigation.

  9. 2020-08-06

    Monterrosa family files a federal civil rights lawsuit against the city of Vallejo and Jarrett Tonn.

  10. 2020-10-02

    Protesters demonstrate outside Governor Gavin Newsom's residence on the four-month anniversary of Monterrosa's death; 17 protesters are arrested.

  11. 2020-12-21

    Michael Nichelini is served with a notice of termination in connection with the evidence destruction investigation.

  12. 2021-02-10

    U.S. District Judge Troy L. Nunley denies Tonn's motion for a change of venue.

  13. 2021-04-02

    Michael Nichelini is fired by the city of Vallejo; Officer Fabio Rodriguez is suspended for 40 hours.

  14. 2022

    An independent third-party investigation finds Tonn violated department policies; Tonn is fired from the Vallejo Police Department.

  15. 2022-12

    An arbitrator overturns Nichelini's termination and orders reinstatement with back pay.

  16. 2023-08-18

    Detective Jarrett Tonn is cleared and reinstated with full back pay in a binding arbitration decision.

Best coverage

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People

  • Michael Nichelini

    CHARGED

    Vallejo police officer and police union president investigated and fired in connection with the unauthorized destruction of evidence (the truck windshield); termination later overturned by an arbitrator with back pay awarded.

    citation on file

  • Jarrett Tonn

    CHARGED

    Vallejo police detective who shot and killed Monterrosa; fired by the department in 2022 following an independent investigation but later reinstated with back pay in a 2023 arbitration decision that found his use of force legally justified; named as a defendant in a federal civil rights lawsuit.

    citation on file

  • Sean Monterrosa

    VICTIM

    22-year-old man shot and killed by Vallejo police detective Jarrett Tonn on June 2, 2020.

    citation on file

Places

Walgreens parking lot area, Vallejo, California

38.1231, -122.2497

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Common questions

What happened to the victim?
Sean Monterrosa, a 22-year-old man, was shot and killed by Vallejo, California police detective Jarrett Tonn on June 2, 2020, while kneeling with his hands above his waist; police said Tonn mistook a hammer in Monterrosa's pocket for a gun.
Where did the killing happen?
Walgreens parking lot area, Vallejo, California.
What is the current status of the case?
Status: ongoing.

Sources

  1. Killing of Sean Monterrosawikipedia · Wikipedia · 2026-07-07
  2. Contemporaneous coverage — San Francisco Chroniclenews · San Francisco Chronicle · 2026-07-07
  3. Contemporaneous coverage — The Guardiannews · The Guardian · 2026-07-07
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