Widow Chen Peixia holds a photo of slain New York Police Department officer Liu Wenjian at Liu's funeral in Brooklyn of New York City, the United States, Jan. 4, 2015. Liu and his parter Rafael Ramos were fatally shot in the head as they sat in their patrol car in Brooklyn on Dec. 20, 2014. The killer, Ismaaiyl Brinsley, who killed himself soon after, had said he was seeking to avenge white police officers' killing of two unarmed black men this summer.  [Photo/CFP]