Crime scene: 162 mystery solving puzzles to find out who the murderer is

Chapter 101 The Fruit Knife Exposes the Murderer

One morning, a loan shark was stabbed to death with a fruit knife in his hospital bed.The murder weapon was found in the hospital garden.Since the murderer wrapped the knife with a cloth during the attack, no fingerprints of the murderer were left on the handle of the knife.But when the fruit knife was discovered, careful detectives found that there were many ants crawling on the handle of the knife.The hospital was not yet open at the time of the murder, so the police believed that the murderer was probably also a hospital patient.

After investigation, the three patients were the most suspected, they were: intestinal tuberculosis patient in ward 3, diabetic patient in ward 5, and nephritis patient in ward 7.When the detective saw the list, he quickly pointed to one of them and said, "The murderer is this patient."

Which one is the murderer?Why is the detective so determined?
[Answer] When the murderer commits the crime, his palms will sweat due to nervousness, and diabetics are more likely to sweat than normal people, and the sweat also contains sugar.The murderer wraps the handle of the knife with a cloth, and the palm of the hand sweats during the attack, and the sweat adheres to the handle of the knife through the cloth.After he discarded the knife, the handle attracted ants.Therefore, the diabetic patient in Ward 7 is the murderer.

(End of this chapter)