So I'm the worst at coming up with the mystery/thriller plot elements, but for my soon to be WIP I want to inject some of that to push my boundaries a little. I write romance, so the true story is about two people falling in love and making lots of nookie - but I still want the subplot to make sense. In a nutshell, MC #1 buys an old crappy house in an upcoming neighborhood order to flip it (i.e., fix it up and sell for a large profit). After a few disturbing incidents, he starts to think that the house might be haunted. For story purposes I want the haunting to be faked, but I can't seem to come up with a non-corny reason you'd try to gaslight someone into believing their house is haunted other than the tired old "buried treasure in the walls" trope. This is for the most part a lighthearted meet-cute romance, so I don't want the underlying reason to be too dark (the bad guy buried dead babies and doesn't want them to be discovered - considered and rejected), but enough that there's some element of danger in the final confrontation. Any suggestions are cheerfully welcomed!