In the La Montaña region of Guerrero, Mexico, homicide is the leading cause of death—and the police have a reputation for corruption, excessive use of force and extrajudicial killings, says peace psychologist Eduardo I. Diaz, PhD.

"In many Latin American countries, the police are very poorly paid and they sometimes find a way to make ends meet by doing things they shouldn't be doing," says Diaz, who in addition to consulting worldwide on independent oversight of law enforcement heads the Miami-Dade County office that addresses complaints about the police or other county employees.

Last summer, to help repair the relationship between La Montaña's police and the community, Diaz began advising Mexican nongovernmental organizations on ways to ensure that officers not only control crime, but also treat their citizens fairly and respectfully.

But how does one build trust between police and civilians in an area crippled by generations of lawlessness, such as Guerrero? It's a long and complicated process, but communities must begin by choosing a respected community member who can serve as a liaison between civilians and police. Such an able—and willing—person is not easy to find, nor is it a simple role to navigate. Some police unions are very aggressive and have the money and power to influence local politicians, says Diaz, who credits his upbringing in Miami as a Cuban Quaker with shaping his 25-year quest to promote peace with justice.

"It's risky in the sense that anybody's who's involved with civilian oversight will get shot at—if not physically at least verbally," says Diaz, who's been a target himself as a peace broker.

However, such attacks only serve to motivate him, and although the civilian oversight process is just getting under way in La Montaña, if it's successful, it could serve as a model for other regions that face similar problems, he says.

"In my business, if someone is not criticizing you, you are not doing your job because that means you are playing it safe and not really confronting injustice."

—E. Packard