The gardener could be a suspect. He was always around the mansion, knew all the secret paths and hiding places. He might have found out some dark secret of the victim and decided to take revenge during the storm.
The killer could be the old butler. He had the keys to all the rooms and a mysterious past. Maybe he was seeking revenge for something that happened in the mansion long ago.
In the 'Murder at Old Fields Story', the suspect could be a local who had a grudge against the victim. Maybe the victim did something to anger the local community, and this person decided to take revenge. Another possibility is a stranger who happened to be passing through Old Fields. They could be a criminal on the run and saw the victim as an easy target. Or perhaps it was someone who was involved in illegal activities in Old Fields and the victim found out and was about to expose them.
As I don't know the details of 'the watcher murder story', I can't determine who the main suspect is.
It could be an unknown person who has been sneaking into the building and using the secret room for their own purposes. This person might have a connection to the building's past or present occupants, but has managed to stay hidden until the mystery of the room is discovered.
Since I haven't actually read 'Murder at TopHouse: A Crime Novel', it's difficult to determine the main suspect. It could be someone who has a hidden motive, perhaps related to a past event that the victim was involved in. Maybe there's a character who has been acting suspiciously throughout the story, like someone who was overly interested in the victim's affairs or who had a strange alibi. The author might have planted subtle clues throughout the narrative to point towards the main suspect.
The killer could be the local shopkeeper. He had a grudge against the victim because the victim was spreading rumors about his store not having good Christmas deals. So, he planned the murder during the Christmas shopping season.
The main suspect was Leo Frank.
You could have a mystery where a group of people are invited to stay in an old mansion for the weekend. During their stay, they start to hear strange noises at night. One of the guests goes missing. The remaining guests find a hidden room in the mansion that seems to hold a dark secret from the past. Maybe it was a place where illegal experiments were carried out long ago.
Edgar Allan Poe also contributed to the old murder mystery genre. His works, such as 'The Murders in the Rue Morgue', are considered early examples of detective fiction. Poe was a master at creating an atmosphere of horror and mystery, which set the stage for future murder mystery novels.
I can recommend a Taiwan romance novel called "Assassin Rhapsody". It tells the story of the female protagonist, a successful businessman, who accidentally witnessed the male protagonist's murder process and was involved in the world of assassins. The male protagonist's series of protection and pursuits to protect the female protagonist had also created feelings between the two. I hope you like this fairy's recommendation. Muah ~😗