Detective Smarttypaunts arrived at a suicide case. The man was the rich millionaire Dr. Snoot. Apparently, he hanged himself in his attic with a small stool and belt. The only witness was Dr. Snoot’s butler. The butler’s story was that he was outside bringing in groceries when he looked up and saw his master through the small round attic window kicking over the stool. Immediately, the Detective knew the man was lying and arrested him. What tipped off Detective Smarttypaunts?

Solution
If the butler was looking up into the attic, he couldn’t have seen the Doctor kick the small stool—the attic would have been too high up for someone on the ground to see the stool through.