Can you find that way and tell the police so you are not sentenced for the crime you did not commit?

Question

You are living at you place alone. You own a shed which has been locked. The lock that has been placed on the door can be closed without a key but need the key to be opened. You collected some old stuff and decided to keep it in the shed. After keeping the things, you locked it back. The next day, the police found a dead body inside the shed. As you are the only one living in your house, the police has nothing else to believe than you are the murderer. But you have not committed any crime.

There is a way the murder would have happened. Can you find that way and tell the police so you are not sentenced for the crime you did not commit?

Answer 1

The door can be closed without a key.
The murderer took the lock hanging on the door and replaced it with an identical one while you were keeping old things in the shed. After you left the murderer opened the lock with his key, put the body inside, replaced the lock with the initial one and closed the door.