NEW YORK (PIX11) — NYPD officers started to take part in a four-day active shooter training through a series of simulations.

After a string of gun violence incidents, most prominently the subway attack in Brooklyn that took place in April, the program to prepare cops for active-shooter events was initiated.

“It’s important that we are constantly in a state of readiness,” said Raymond Porteus, commanding officer of the Transit Bureau. 

Many of the trainers were former military and police officers that have expertise in the matter, according to Porteus. The simulation involved containing “gunmen,” as well as treating “injured victims” on the scene.