There are two films here. The first is the story of a sociopath who commits a murder just to commit it. There is no gain. There is no vengeance. There is no passion. For whatever reason, this is a pretty bad guy. He is brutal to people, striking out at them without provocation. We know it was just a matter of time. His killing is brutal and endlessly vicious.
The second half involve the action following his trial. He has been sentenced to death. He is full of classic paranoia. His lawyer, a victim as well, doing his first capital case, must respond to the claim that the jurors had it in for him by telling him they were against his crime. We see the human side of the man as time winds down. There is also a brutal, graphic portrayal of a hanging and all the leads up to that. Quite gut wrenching.