'I received an anonymous letter from New York giving me all the details of the scene.
The letter was written with the evident intention of injuring Mr.Van Torp.

Whoever wrote it must have heard what you said to each other, and perhaps he was watching you through the keyhole.

It is barely possible that by some accident he overheard the scene through the local telephone, if there was one in the room.

Should you care to see that part of the letter which concerns you?
It is not very delicately worded!' Margaret's expression had changed; she had dropped her hands and was leaning forward, listening with interest.
'No,' she said, 'I don't care to see the letter, but who in the world can have written it?
You say it was meant to injure Mr.Van Torp--not me.' 'Yes.

There is nothing against you in it.