Cops are not the only ones who wear body armor. Crooks do too, like the robbers in the 1997 Hollywood shootout.
This is the reason for the Mozambique Drill (two to center-mass, then one to the head). A variant is to shoot the pelvis (an easier target than the head and one which will likely put the bad guy on the floor)
Unless he was wearing a kevlar codpiece. Which, suprisingly, they do make. They call it a “groin protector”. Bulletproof boxers.
CC