The Akron Police Department training class works out at Kent State Basic Police Officer Training Academy. Donald Clayton is the only African-American in the class of 20. M.L. Schultze/WKSU hide caption

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New York Police Department Commissioner William Bratton attends a press conference after witnessing police being retrained under new guidelines at the Police Academy on Dec. 4. Andrew Burton/Getty Images hide caption

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There's been a sharp decline in the number of arrests and tickets and summonses issued in New York City. Police sometimes use work slowdowns to show dissatisfaction with policies, workloads or contract disputes. Justin Lane/EPA/Landov hide caption

itoggle caption Justin Lane/EPA/Landov

Protesters and law enforcement officers face off during a protest outside the Ferguson Police Department in October. Ferguson police statistics show the department arrest blacks at a higher rate than other racial groups — but that disparity is true for police departments across the country. Charles Rex Arbogast/AP hide caption

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Mike Myers is the roving village public safety officer serving southwest Alaska villages including Manokotak. Like many officers in rural Alaska, Myers doesn't carry a gun and often doesn't need one. Martin Kaste/NPR hide caption

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Bush pilot John Bouker (right) and village public safety officer Mike Myers (left) outside Bouker's Cessna 207. Bouker transports Alaskan cops to remote areas and helps pick up prisoners. Martin Kaste/NPR hide caption

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Apple, which unveiled iOS 8 at June's Worldwide Developers Conference, says it will be technologically unfeasible for police to extract data from its new operating system. Justin Sullivan/Getty Images hide caption

itoggle caption Justin Sullivan/Getty Images