None of this is right.
The whole situation is wrong.
The structure that the cops exist in is wrong.
The law structure is wrong.
The court system is doubly wrong.
Still, it looks like a person was convicted for doing the thing that the police department said to do is this particular case... and that he did it with extreme prejudice and planned to kill the person.
And still, there is rioting.
I'm less sure he planned to kill him, he just didn't care enough to not kill him. To be a cop is to have mental problems.