This was featured on unsolved mysteries and is the topic of books, and a movie called a place in the sun.
Books will mysteriously fall off of shelves and it will be the book that you were looking for.
People say that they can feel him watching them work when they work down in "the dungeon".
Sometimes it appears as if someone is walking through.
They will check the system to see who accessed the Becker House and see that no one has. Workers there have heard noises upstairs even though it is now vacant on that floor.
From outside you can see a man standing in the window sometimes.