The Case of the Murdered Doctor

The body of Dr. Chris Willis lay slumped over her desk. An arrow was sticking out of her back. Her husband discovered her that way in the morning and immediately called the police. Detectives Davis and Moreno were soon at the scene.
“I haven’t seen a case like this before,” Davis remarked as he examined the position of the body. “It appears that someone shot the arrow from the backyard. Then it went right through the screen and hit her while she was writing at her desk.”
“I can’t imagine who would do such a thing,” her husband exclaimed. “She had no enemies that I know of.”
“Perhaps it was the work of a thrill killer,” Moreno suggested. “It is possible that her assailant didn’t even know her at all. It might have been a stranger who saw an opportunity to commit a murder and get away with it without any other motives.”
“You might be right,” Davis replied. “What ever the case, we shall be sure to investigate any possible lead. The fact that the murderer used a bow and arrow might give us some clues.” He looked at the arrow thoughtfully. “I don’t believe that there can be very many of this type of arrow in town. I think that we should go to archery shops and try to trace where this might have been sold.”
After making several calls, the detectives found that there were only three stores in town which sold that type of arrow. One of the stores hadn’t sold any arrow like that for several years and the owner couldn’t help the detectives much with sales records. However, Davis and Moreno did get some leads from the other two stores and they were able to talk to several possible suspects.
Detective Davis told everyone the same information.
He said, “Dr. Willis has been shot. Do you know anything about it?”
Lenny Archer said, “I don’t know anything about it. I don’t even know Dr. Willis. I can’t help you. I don’t even own a gun anyway.”
Robin Hoodman said, “Doctor? No, I don’t know any doctor. I haven’t heard anything about it. If you leave me your number, I’ll get back to you if I can be of any help.”
John Little said, “No, never heard of her. I don’t know anything about her death.”
Charles Yeoman said, “I don’t know anything about it. I certainly had nothing to do with it. I do own some weapons, but I would never hurt anyone that way.”
Cindy Bow said, “Is Dr. Willis dead? That’s terrible. Yes, I knew her. I am so sorry for her family. No, I didn’t know anything. I am so shocked. Honestly, this is the first time I’ve ever heard of it.”
Davis turned to Moreno. “I think I’ve got a suspect,” he said.

WHO DID DAVIS SUSPECT?

THE ANSWER
He suspected John Little. Little knew that Willis was a woman, even though Davis never mentioned her gender. He also knew that she was dead, even though Davis never mentioned whether or not Willis was alive. A further investigation revealed him to be the culprit.