Ohhhh boy. This is a good intro! It actually sets up a nice haunted-house-ghostbusters-luigi's-mansion-scooby-doo sorta story. Many different paths open, and many different options ahead.
However you say it's gonna have murder and stuff.
So scrap all that and replace it with some deep crap. Maybe some Us, and stuffs.
Otherwise, you got a nice setup!
Keep writing! And we will keep reading!