Annie Nodes was found dead in one of the bedrooms by her servant, Wilfred. Wilfred tells the story to the detective Sherlock Holmes: As soon as I finished the work I noticed that her study light was on and so I decided to peek in to check if she was in there. There was frost all over the window and so I wiped it away to see inside. That is when I saw her body and I immediately kicked open the front door. I called the police immediately afterwards. After listening to the entire story, Sherlock Holmes could immediately discover that the killer was the servant. Guess How?