Detective Henderson was on his way to the big city auto show when he decided to visit his old friend, Dr. Saul. At Saul's home he was shocked to learn that just two days earlier his long time friend had hanged himself.

"Saul was in excellent health and spirits when I heard from him last week," Henderson told the sheriff. "I can't believe he committed suicide."

"But he did---I investigated it myself," said the sheriff. "Here's how it all happened."

"Pierce Payne, Saul's manservant, was returning to the house late that night when he spotted a light in the attic. As Payne got out of his car, he saw through the open attic window Saul knotting a rope around his neck. The other end was tied to a rafter. Then he saw Saul calmly kick away the small stool he was standing on, and that was the end.

"Payne found the house locked. He had forgotten his key; so he went to the neighbor to call me."

"He repeated to me exactly what I've just told you," said the sheriff.

"When I arrived at Saul 's house, I had to force the front door open." Payne and I then ran up the three floors to the attic. Saul was dead. The coroner has no doubt that death was from hanging."

"The attic floor was clear except for the little stool that lay overturned by the door," concluded the sheriff.

"Let's go out to the house," said Henderson. "From everything you've told me about Payne's story, I can tell you he's lying!"

How did Henderson know that Payne was lying?