VALLEJO (CBS SF) — Vallejo police announced Wednesday the death of a suspect shot early Tuesday morning during looting incidents by an officer who mistakenly thought he had a gun.

During a Wednesday afternoon press conference at Vallejo City Hall, Police Chief Shawny Williams said 22-year-old San Francisco resident Sean Monterrosa was shot and killed by an unidentified officer who thought Monterrosa had a gun in his pocket, but instead it was a hammer.

READ MORE: Santa Rosa Firefighters Contain Small Grass Fire Sunday Afternoon
Williams said police officers arrived at a Walgreens on the 1000 Block of Redwood St. which was being looted at the time and two vehicles, a silver pickup truck and a black sedan drove away from the scene with officers chasing them. The sedan rammed a police car as it fled and injured an officer, Williams said.
Simultaneously, Williams said, other officers came upon Monterrosa, who appeared to be trying to get into the sedan and looked to be carrying a weapon.
“This individual appeared to be running toward the black sedan but suddenly stopped, taking a kneeling position and placing his hands above his waist, revealing what appeared to be the butt of a handgun,” said Williams. “Investigations later revealed that the weapon was a long, 15-inch hammer tucked into the pocket of his sweatshirt. Due to this perceived threat, one officer fired his weapon five times from within the police vehicle through the windshield, striking the suspect once, fatally wounding the suspect.”

Raw Video: Vallejo Police Chief Announces Fatal Officer-Involved Shooting

Monterrosa was taken to the hospital where he was pronounced dead. No body cam or dashcam footage of the shooting was released but Williams said it would be made available “as soon as we can.”

The officer who fired on the suspect is a 13-year veteran and would be identified in the coming days.

Williams said Monterossa has an extensive criminal history including attempted murder, assault with a deadly weapon, and illegal weapons and drugs.

The press conference ended abruptly when some Vallejo residents gathered at the press conference outside city hall began to shout at Williams, demanding answers as to why the officer opened fire on a suspect who Williams described as being on his knees.

“At what point do you arrest him and make an example out of all these officers and arrest him?” shouted one woman. “Fire him! Not paid leave! Fire him for killing a man that was on his knees!”

Williams reiterated that the officer perceived a threat from the suspect and his posture and that an investigation would determine whether it was a lawful use of force.

In an emailed statement issued after the press conference, Williams appeared to clarify his earlier comments at the press conference, saying the suspect “abruptly turned toward the officers, crouching down in a half-kneeling position as if in preparation to shoot, and moving his hands toward his waist area near what appeared to be the butt of a handgun.”

Williams said the police department and the Solano County District Attorney’s Office would launch separate investigations into the shooting. On Tuesday, Vallejo Mayor Bob Sampayan vowed the investigation would be “open and transparent.”

Vallejo has now seen two nights of violence and the city enacted an 8 p.m. curfew after Monday night’s shooting and civil unrest, which included several incidents of looting and a fire set inside City Hall. A curfew was later ordered for all of Sonoma County as well as other Bay Area counties to help quell the ongoing civil disturbances.

READ MORE: Temperatures Will Soar Into Triple Digits By Mid-Week

Monterrosa’s family is now working with civil rights attorney John Burris. Vallejo residents who were on hand to reject the chief’s description of the shooting noted how has long been criticized over its use of force and alleged police misconduct.

“Like I said, the police have been historically violent in this city,” said Maui Phil, who came to hear the chief speak.

“There was a sniper on the roof two streets over,” said Jenny, a Vallejo resident who lives near the recently-embattled police station. “We stayed in a hotel two nights in a row because of this. I have an eight-year-old, and all she heard was gunshots.”

Jenny has been collecting the non-lethal weapons discharged by police during confrontations outside her home. Those lead to the brief deployment of the National Guard overnight.

“Last night the guards were placed in certain areas, to guard certain areas,” Williams said. “They’re not patrolling the city.”

Vallejo is now hoping for a de-escalation after the past two nights.

“I would assume that they would come back, I would hope, to protest again, peacefully,” Jenny said. “But I don’t want to see anybody getting hurt.”

MORE NEWS: Grandmother Dies; Son, Grandson Injured In Highway101 Crash In Healdsburg

Wilson Walker contributed to this report.