New York Mayor Bill de Blasio (center), City Police Commissioner William Bratton (second from right) and other NYPD officers address a news conference on Jan. 5. There is debate surrounding the citywide increase of low-level crime enforcement, otherwise known as the broken windows approach to policing. Richard Drew/AP hide caption

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This undated photo released by the New York City Police Department shows officer Brian Moore. Moore, a New York City police officer, was shot in the head and critically wounded while attempting to stop a man suspected of carrying a gun. AP hide caption

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Multiple lawsuits accuse the New York City Police Department of pressuring officers into fulfilling monthly quotes for tickets and arrests, resulting in warrantless stops. The NYPD denies the allegations. Spencer Platt/Getty hide caption

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Reginald Britt first moved into the Taft Houses, a public housing complex in East Harlem, in 1976 Alexandra Starr 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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New York City Police Commissioner Bill Bratton speaks during an NYPD swearing-in ceremony in New York on Jan. 7. He confirmed to NPR today that there had been a work slowdown by officers in the weeks since two police officers were shot dead. He said the matter was being corrected. Seth Wenig/AP hide caption

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New York City police officers march before funeral services for police officer Wenjian Liu at Aievoli Funeral Home, in Brooklyn on Sunday. Liu and his partner were gunned down in an unprovoked attack on Dec. 20. Julio Cortez/AP hide caption

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Vice President Joe Biden, center, arrives for funeral services for New York City police officer Rafael Ramos at Christ Tabernacle Church, in the Glendale section of Queens, on Saturday. Julio Cortez/AP hide caption

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Protesters march through Midtown Manhattan on Tuesday, a day after New York City's mayor called for a pause in the demonstrations. Michael Graae/Getty Images hide caption

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New York Police Department Chief of Detectives Robert Boyce said Sunday that a gunman told bystanders to follow him on Instagram, then shot and killed two police officers in Brooklyn on Saturday. Stephanie Keith/Reuters/Landov hide caption

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In this frame grab taken from video provided by the New York Police Department, an unidentified man approaches New York City police officers with a hatchet Thursday. The man was fatally shot by police after he wounded two officers. AP hide caption

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This image obtained by NPR shows Ahmed al-Moflihi, a Yemeni-American who is believed to have fought in the Syrian civil war. NPR hide caption

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