Give them that key. Let them go and look in the room where the pipes are. Then they'll see for themselves that there's no ghost.
8 seconds sound clip from the Fugue in C Minor (Suspense) classic radio play.
You can hear this line at 00:18:50 in the radio play.
Quote context
[...]
- What are you doing here? David, did you strike Miss Peabody?
- He's sick. I'm sure he's very sick.
- Now, go to your room at once!
- Oh, those dreadful children. I tell you, they'll ruin whatever happiness we might have.
- Key? Who told you about a key to that room?
- I'm going to tell you something. Something I've never told to a living soul. It may frighten you.
- Margaret was going mad when she died. No one knew it but me. It ran in her family.
- And now you think the children...?
[...]