OAKLAND (CBS SF) — Oakland police Chief Sean Whent and Mayor Jean Quan pledged Wednesday that police will change their tactics in future protests to try to prevent the acts of violence that occurred in protests on recent nights.

After meeting with business owners who expressed concern that the violence committed by some people who participated in protests against the acquittal of George Zimmerman in the Trayvon Martin shooting case in Florida will hurt their businesses, Whent said he will increase the number of officers who are available for future protests, including one that’s planned for Saturday.

Speaking at a news conference on the steps of City Hall, Whent said, “We’re taking the steps necessary to try to prevent these types of problems in the future.”

He said one step will be to keep officers closer to demonstrators “so they’re more visible and there’s more of a police presence.”

He said that in contrast to Monday night, when a protest spiraled out of control and demonstrators blocked a freeway, smashed store windows and engaged in other acts of violence, there were officers on duty Tuesday night and “we were more successful in preventing violence and crime.”

Whent said that during the rally and march planned for Saturday, “We will have every available police officer on duty so we have sufficient staffing to prevent crimes from occurring and if they do occur to make arrests.”

Joining Whent at the news conference, Quan said, “We’re changing our tactics so we can be a lot more flexible” in responding to protests and making arrests if necessary.

Quan also said the city is working to provide resources to the city’s understaffed Police Department, such as getting better technology and more new cars.

In addition, city officials have authorized more overtime for officers until the department is able to increase its staffing level, which is being built up gradually through ongoing training academies.

Whent said, “The size of the Police Department really is a factor” in its ability to respond to large demonstrations.

The chief said he understands the concerns that business owners expressed when he met with them at Oakland Chamber of Commerce headquarters, including the cost of replacing broken windows, scaring customers away and frightening employees.

“It’s a real economic hardship for their businesses,” Whent said.

He said he tried to reassure the business owners by telling them about the city’s plan for coping better with future protests.

Alameda County District Attorney spokeswoman Teresa Drenick said her office filed charges Wednesday against three of the nine people who were arrested during the protest Monday night.

The other six people were cited and released and prosecutors will decide later whether to charge them, she said.

Lamar Caldwell, 27, and Tanzeen Doha, 34, were both charged with felony vandalism for allegedly breaking a glass storefront window at the Men’s Wearhouse at 300 Frank Ogawa Plaza valued at more than $400.

Oakland police Officer Gregg Williams said in a probable cause statement that officers saw Tanzeen “swing his right arm above his head while holding an object in his hand and strike the window of the Men’s Wearhouse with the object,” causing the glass in the window frame to crash down.

Officer John Romero said in a probable cause statement that officers saw Caldwell “using an unknown object to strike the large storefront window at least two to three times until the window shattered.”

Romero said Caldwell “was unprovoked” and “intentionally and maliciously broke the window with the intention of causing property damage to the business.”

Drenick said Caldwell was arraigned in Alameda County Superior Court today and was ordered to stay away from Broadway between 14th and 15th streets, which is the area near the Men’s Wearhouse. He’s in custody in lieu of $10,000 bail, she said.

However, Drenick said Zoha failed to appear in court Wednesday after he was released on bail so a $10,000 bench warrant was issued for him.

Jeffrey Clark, 30, was charged with one count of misdemeanor battery on a police officer and one count of misdemeanor assault for allegedly attacking a second officer on Monday night.

Officer Francisco Negrete said in a probable cause statement that he saw Clark “pick up a rock from the ground and intentionally throw it at me,” hitting him in his left shoulder.

Negrete said Clark fled into the crowd but when police were in the process of arresting a suspect “Clark then again picked up another rock and raised his right hand over his head in a throwing position” so he took Clark into custody.

Drenick said Clark will be arraigned at a later date.

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