VALLEJO, Calif. (KRON) – One year ago today, Sean Monterrosa sent a text message to his sisters asking them to sign a petition for Justice for George Floyd.

Minutes later, he was shot and killed by a Vallejo police officer.

Sean was kneeling in a Walgreens parking lot.

The officer shot him through the windshield of an undercover police car five times, thinking Monterrosa had a gun — But he had a hammer in his pocket.

The 22-year-old’s death sparked protests across the Bay Area and a federal civil lawsuit was filed.

Monterrosa’s sisters, Michelle and Ashley, also got to work.

The two sisters have been fighting for justice for their brother for the past year, working on legislation, going to the capital, protesting, phone banking.

“The work we do is not just for Sean. It’s for so many families. We will continue to make these sacrifices because at the end of the day. Our voices need to be heard,” Michelle and Ashley Monterrosa said. 

The sisters stepped away from their full time jobs and school to focus on their mission.

“Obviously we would love for Sean to be here and it’s just so painful that someone could just take your loved one’s life in an instant,” they said. 

The investigation into Monterrosa’s death is ongoing.

Just last month, the attorney general announced the Department of Justice will conduct an independent review of the Vallejo police investigation.

Vallejo police destroyed the windshield of the police car and the vehicle itself was put back into service just days after the shooting.

The officer who shot Monterrosa had also been involved in three other shootings within just 5 years, according to the attorney of the Monterrosa family.

Vallejo police have bodycam footage but no dashcam video that would ultimately show Monterrosa in the moments leading up to being shot.

Friends and family will remember him this weekend with events planned in San Francisco where Monterrosa was born and raised.

“I truly believe the only way he can truly rest in peace is once all the officers involved in his murder do get brought to justice,” Maricar Bamba, former tutor and friend, said.

The Vallejo Police Department has sent the following statement to KRON4 in response to a request for comment:

We are mindful that today marks the one-year anniversary of the death of Sean Monterrosa. It is important for us as a City and Department to acknowledge that his death was a tragic event and loss of life, creating a void in his community. At this time, we are thinking of the Monterrosa family, and words fall short of expressing our sympathy to his loved ones on this very difficult anniversary.