He got up. He had the gun. They ordered him to drop the gun. He refused to drop the gun, and that's when the officer shot him.

The problem here is easy access to a firearm. Here is someone who never should have had a gun that had a gun.

Riley ordered him to drop the knife and drop to the ground, and the suspect refused to do so, forcing Riley to fire in self-defense,

The gun went off accidentally.

we are not prepared at this time to say that any one person is responsible for these homicides. This case is by no means closed.

There's really only one way out and one way in. Once he's inside and by that front door, he's got them cornered.