Secrets and Mysteries. The Castle with Ghosts

1 riddle, 2 detectives, 5 chapters to find the solution.
Your first investigation!
When a mysterious murder occurs in the North Bonny castle, everyone suspects an evil spirit, and only Linsey, the young heir of the Maclean clan, understands that something is amiss. The girl decides to conduct her own investigation and prove that there is nothing mystical about the incident. But where to start? How to become a detective if you have never solved a detective puzzle before? Linsey realizes that to get to the truth she will have to delve into history. Join her in the investigation.
Interview witnesses, record hypotheses, examine evidence. Get ahead of your literary rival and guess first who committed the crime.
Will you dare to join the game?..