The Dink Network

Ok...I think i came up with my own riddle, hehehe. A man was found dead in the basement from a hard hit into the head. He had a cracked skull and was bleeding. There was a tall wooden shelf behind where the man was. The shelf was standing right next to the wall with a crack on the top shelf. There was a can next to him and a picture of a man and a tree in front of him on the floor. No one had broken into the house and he lived alone. How did he die and what was his job?

(Yes or no questions)