The NYPD has reportedly spotted posts on social media calling for cop killings on New Year's Eve, following a period marked by an uptick in threats made against police officers. DNAinfo reports that gang members have taken to Twitter to make threats against cops, using hashtags like #wingsonpigs and #onlydeadcops. Some of these tweets call tonight "Kill A Pig Night" and "New Year's Eve Massacre 2014." The NYPD has been investigating a large number of threats made against the department recently, following the fatal December 20th shooting of Officers Rafael Ramos and Wenjian Liu. DNAinfo reports that cops have arrested...