Riddle: Old Mr. Tidy was found dead in his study by Mr. Fiend. Mr. Fiend recounted his dismal discovery to the police. "I was walking by Mr. Tidy`s house when I thought I would just pop in for a visit. I noticed his study light was on and I decided to peek in from the outside to see if he was in there. There was frost on the window, so I had to wipe it away to see inside. That is when I saw his body. So I kicked in the front door to confirm my suspicions of foul play. I called the police immediately afterward." The officer immediately arrested Mr. Fiend for the murder of Mr. Tidy. How did he know Mr. Fiend was lying?
Answer: Frost forms on the inside of the window, not the outside. So Mr. Fiend could not have wiped it off to discover Mr. Tidy`s body.