The store room of your house is locked with a certain lock that can be closed without a key but requires a key to open which you own (there is no duplicate key). You decide to move your old stuff in the storeroom. After keeping the things carefully, you lock it back again perfectly. The next day, a dead body is found in your closed store room. Since only you have the key to the store room and you live alone, the police suspects you as a murderer. You can’t understand anything when suddenly a thought strikes your mind. There is a possible way using which the dead body could have been placed by someone else.
Can you find that way so you can tell the police and prove yourself to be innocent?
Solution:
When you were inside the shed, the murderer replaced the lock with his own one that was identical to your original lock. When you locked the store room, you did not require a key and there was nothing abnormal for you. When you left, the murderer opened the lock with his key, planted the dead body inside and replaced the lock again putting the original lock in the place. He then closed it without any problem.