Two New York Police Department officers were ambushed last weekend by Ismaaiyl Brinsley after he had made threatening posts online, including references to high-profile cases of white police officers killing unarmed black men and a vow to put "wings on pigs." After shooting the officers, Brinsley ran into a Brooklyn subway station and committed suicide. The killings of Officers Wenjian Liu and Rafael Ramos have raised concerns in the already tense nationwide debate surrounding police conduct.