In season 15, episode 6 or 20, a man in a wheelchair fires a gun at officers and the camera crew, no one is hurt, he then fires again at security guards, hitting one in the leg, he survived, officers then open fire on the man in the wheelchair, killing him. You can see blood (this was heavily edited for television).
Lots of violence throughout the series including fights (sometimes with weapons), people getting tased or pepper sprayed, car crashes, police tackling criminals, shootings, etc. The violence is not gory or extremely graphic but it can get very brutal and intense.
In a few episodes across the series including the homicide special edition episodes, dead bodies are shown, but are blurred and/or have black bars on them, example: in one of the earlier seasons, LA detectives find a body in a hotel room, it is implied that the victim was shot and killed, in another episode, a man confesses to fatally shooting his brother over a piece of pizza, his brothers body is seen lying on the side, the body is blurred.
In a season 22 episode, Minneapolis police chase a truck with 2 people inside, the truck crashes, both people are pulled from the vehicle, one of the occupants is so badly bloody and injured, that his entire body was blurred.
In a Season 23 episode: cops are forced to shoot a woman to prevent her from harming herself/her family, shots are heard and she is seen laying on the ground in pain, she survives.
This show's main focuses are on cops and criminals.