Preparations beforehand
Editor: Zayn_
What was the killer's goal?
The things on the table!
If Kieran was correct, on that night that Mary's mother was killed, the things that the killer took were probably a counterfeit.
A counterfeit so real that one couldn't even differentiate it in a short period of time.
Only then would the killer come back to Swusters Castle after some time and set the place ablaze to vent his anger. The killer might have toppled Swusters Castle upside down and still couldn't find what he wanted.
Kieran wasn't sure how Mary's mother could produce such a counterfeit to fool the killer, but he had his own guesses about Mary's mother's arrangements.
Maybe the killer really did assassinate her, but the killer might have neglected what Mary's mother was really concerned about. Eventually, he was trapped in her set-ups.
From the start, when Mary's mother felt something was wrong, all she cared about was Mary's safety. No matter what plans she had, they were all revolving around Mary as the center.