Listen through the keyhole
From Create Your Own Story
"Vernon," Aunt Petunia says in a quivering voice, "look at the address - how could they possibly know where he sleeps? You don't think they're watching the house?"
"Watching-spying-might be following us," mutters Uncle Vernon wildly.
"But what should we do, Vernon? Should we write back? Tell them we don't want-" Petunia stutters.
"No. No, we'll ignore it. If they don't get an answer... Yes, that's best. We won't do anything."
"But-"
"I'm not having one in the house, Petunia! Didn't we swear when we took him in we'd stamp out that dangerous nonsense?"
Then the knob starts to turn.
