A 34-year-old Maths teacher was found dead in the Upper Street Hotel last night. Detective Kent went to the hotel and tried to find clues. To his disappointment, he found nothing valuable for the case. The door was closed and the windows were not broken. There was no sign of fighting. There were even no fingerprints in the room. However, they did find something unusual. In the hand of the body, there was an apple pie! " What does it mean? " Detective Kent thought hard. Suddenly, he thought of something. " I want to know who lives in Room 314, " He said to the hotel keeper. " And ask him or her to the police station right now. " Surprisingly enough, there was no answer. The hotel keeper opened the door and everybody was shocked to find there was also a dead body. On the table, there was a note: I DID IT. I KILLED THE MATHS TEACHER BECAUSE HE CHEATED ME. HE SAID HE HADN' T MARRIED, BUT THIS IS NOT TRUE.
The case is finished. Everyone wanted to know how Detective Kent could find the murderer very much. " Well, it' s a secret, but the answer is not difficult. Let me give you some clues, just think about the pie! "