It's official: the nation's largest police force is delibrately slowing down its work. Police Commissioner Bill Bratton said Friday it's clear that NYPD officers are engaged in a slowdown that has cut summonses by as much as 90 percent in recent weeks. "We're coming out of what was a pretty widespread stoppage of certain types of activity, the discretionary type of activity by and large," Bratton said, adding that major crimes in the city are down. The work stoppage began almost three weeks ago following the execution-style murder of two officers in their patrol car in Brooklyn. It comes amid high tensions between police officers and Mayor Bill de Blasio, whom several hundred turned their back to during the officers' funerals.