Probably a police issued hand gun most likely a variant of the Glock Safe action or Smith and Wesson Military and police or even a Beretta Model 92. Now before we get into seventeen shots means something suspicious, no it doesn't. Despite the movies the Human body is actually quite resilient. There are only three ways the Human body dies. The first is toxic shock, where in due to toxicity the circulatory system of the human body fails. The second is neural shock where in due to damage to the bodies nervous system either directly to the nerve cluster of the lower brain or extreme pain the nervous system crashes and the body stops working. Finally circulatory shock where in due to traumatic injuries the body experiences' extreme blood pressure loss and is no longer able to maintain operation of critical organs and brain blood supply.
Now obviously the first is most likely not applicable. The second and third are. In the case of either placement and ballistics come in. The most common cartridge types in the US are 9x19mm parabellum/ NATO/ Lugar .40 Smith and Wesson, and .45 Auto Colt Pistol. Of these three rounds the first two are the more common service pistol round and both allow magazine capacity matching the numbered shots.
ballistics now come in hollow points vs ball ammo. Both are used by police agencies. Hollow points use hydrodynamic shock or the effect of a round that is supposed to expand in the fluid base of the human body and use the resulting vacuum to damage the tissues, it doesn't always work though and even if it did it wouldn't necessarily be enough to cause either the pain or blood loss to kill. Ball ammo from these rounds is solid and lacks expansion, this can create a ice pick wound channel where the wound is a straight entry and exit with little in the way of destabilizing this wound might cause the body to eventually bleed out but that would take hours.
So if the officer in question felt his life was threatened and he felt the need for lethal force, the effectiveness might not be as instant as some would believe. Even larger caliber fire on the torso and head might not be able to cause enough damage to cause death and as such an aggressive attacker being fired upon can still be dangerous, even if the wounds are lethal. A direct penetration of the heart can still take a minute to cause the body to fail. Alot can happen in that time.
