Robert, an ex employee of Tom

Suspected because he was fired by Tom the day before. I need to know why !

His story : He went to the family's house to complain about being fired. Tom and him went to discuss about it in Tom's office. They had a pretty violent argument, and at some point he hurt himself because of rage. So he went to the bathroom to clean the blood. He stayed there quite a long time to think about his next arguments. Then he heard six gunshots. He locked the door. The killer tried to open the door, then went away.

I don't trust him !