Who can solve the mystery?

Alec Crabtree was found dead at his desk in his study last night. He had been hit on the head with a blunt object. He had been sitting at the desk with his back to the door, and was in the middle of writing a letter. He was found by his wife, when she went in to bring him his bedtime cocoa at 11:15pm but his watch, which had been smashed in the struggle, had stopped at 11:05pm. The suspects are the people who were in the house at the time: Mrs. Crabtree (the dead man's wife), Daniel Crabtree (the dead man's brother), Mr. and Mrs. Fairfax (old friends of the Crabtrees), and Susie (the maid).
Find the first five clues somewhere in this blog!