A person with a long rod bored a hole through the wall and took the keys using the rod. Then, using these keys, they entered the guesthouse, used more holes to unlock the sliding blots with the rod, then walked in and did the killing, then the attacker undid everything, with the help of the rod, and patched up all the holes before leaving.
Kinda roundabout from my perspective, but we have to come up with crazy conspiracy theories to win >_>