As the killing of an unarmed black teen by a white cop roils predominantly black Ferguson, Missouri, one of that community's challenges is replicated even¿ in the highly diverse Bay Area: White police officers disproportionately dominate in cities with large minority populations.
More than 83 percent of larger cities in the region have higher percentages of white police officers than their percentages of white residents, according to U.S. Census estimates -- sometimes by a staggering proportion.
"Race is the elephant in the room" of policing, said LaDoris Cordell, a retired Superior Court judge who is San Jose's independent police auditor.
If an institution that wields power "is to have the respect of the people it serves, it must look like the people it serves," said Cordell, who is black.
In Daly City, which 2010 census data showed had a white population of 14 percent, the census that year estimated that the police force was all white. The census numbers for cities of 50,000 or more people also estimated no officers of color in three Contra Costa County cities: Walnut Creek, Antioch and Brentwood; Novato in Marin County; and the city of Napa.
Many local departments say they have improved in diversity -- and several challenged the zero minority estimate -- which has no single explanation. Many of the communities were historically whiter and have simply changed faster than their police; observers also said that minority youths tend not to be attracted to police work because of how their communities view the institution.
But whatever the reason, some saw a troubling trend in the predominance of white officers, as the Missouri protests ignite a national debate on race and policing.
Lack of police diversity, law enforcers and experts said, undermines perhaps the most important element in policing: community trust.
"Police carry guns and have an immense amount of power over us," Cordell said. "Their effectiveness depends upon the trust that the community has in them. Where there is no trust, people have no investment in following the rules."
The lack of diversity in Bay Area police departments "is surprising and concerning," said Micaela Davis, a criminal justice attorney with the ACLU of Northern California. "There are so many underlying tensions," Davis said. "It happened with Oscar Grant."
The 2009 killing of Grant, a black man who was lying on a BART platform when a white officer shot him in the back, set off weeks of protests in Oakland and elsewhere.
The percentages of white police officers, Davis said, show "underlying problems that have existed in the Bay Area for decades. Looking at the makeup of police departments is part of the solution."
The president of a statewide black officers group agreed.
"It's extremely important to have a police department that reflects the (ethnic) makeup of its community," said Sgt. Bryan Pendleton, head of the California chapter of the National Black Police Association. "It brings an understanding, and it provides role modelsfor young kids."
When he encounters "people who look like me" in a stressful situation, "I tend to understand where they are coming from," said Pendleton, a San Diego police officer. "My fear level is not going to be where a white police officer's is going to be."
In Oakland -- 26 percent white with a police force that has an estimated 49 percent white officers -- minority cops often serve as unofficial recruiters in their communities, said Assistant Chief Paul Figueroa.
The department seeks out officers who speak Spanish, Mandarin and Cantonese as recruiters and has concentrated on convincing young Latinos and African-Americans to consider working in Oakland despite misgivings they might have about the department or police in general.
"We have to take extra steps in those communities to explain why it's important for us to have diversity so that we evolve into the type of organization we want to be," Figueroa said. "When you have people who can empathize with those communities, it makes a big difference."
Oakland Mayor Jean Quan, the city's first Asian-American mayor, said that as the city has diversified, it has more young people who grew up there and are sensitive to the plight of many ethnic groups, making them ideal police recruits.
"It's not just racial, it's cultural. We're not there yet, but we're getting much closer to where we want to be," she said.
But minority recruits are often held to higher standards than others when trying to enter law enforcement, said the Rev. Jeff Moore, president of the San Jose chapter of the NAACP.
"We have to be way above the qualifications. We can't just clear the bar, we've got to be way above the bar," Moore said.
Between white officers and minorities "the relationship can be such an antagonistic one, we sometimes don't see it as a career choice," Moore said.
In San Jose, the census estimated 63 percent of officers are white among a white population of 27 percent.
"We know we are a melting pot and that an officer who has knowledge of the customs of a group will be better able to deal with that segment of the population," said Officer Albert Morales, a department spokesman.
"You can generally see that frustration disappears" when a crime victim and a police officer both speak Spanish, he said. "There's that sense of 'this officer understands, so now I'm going to be more forthcoming.'"
In Napa, a city where more than one-third of residents are Hispanic, the 75-member police department has five Hispanic officers. The others are white, said Capt. Jeff Troendly.
"We are trying to balance things out," Troendly said. "I don't think we are absolutely perfect, but we are actively" trying to recruit more Hispanic officers. The department is moving to a neighborhood policing model that it hopes will help diversify the department's recruitment pool and attract officers who grew up in the city. "We still have room to grow, no two ways about it," Troendly said.
In Antioch, Police Capt. Tammany Brooks, who is black, said the department is obviously not all white as the census estimated. He said he could not detail the department's ethnic breakdown and declined to comment further.
In Mountain View, police Chief Max Bosel said his department was also more diverse than the census estimates, but agreed that diversity was a core element to effective law enforcement. But he added, "It is a constant effort to try to recruit and hire diverse applicants."
Pendleton said too many minority youngsters develop negative perceptions before they ever meet an officer. "You have to catch them early. By the time they are in middle school they already have opinions about police. We have to change their perceptions," he said.
"If we don't do things differently, nothing is ever going to change."
Staff writers Matthew Artz and David DeBolt contributed to this story. Follow Thomas Peele on Twitter @Thomas_Peele.