Here, where there was no window to betray our presence to anyone outside, he switched on a lamp and looked at me more in sorrow than in anger.
"You would have to butt in just that minute, Mr. Burton."
"Sorry," I apologized.
"But I got a hunch that I was on to something."
"And so you were probably.
Did you see anyone?"
I hesitated.
"I'm not sure," I said slowly.
"I've got a vague feeling I saw someone sneak in through the front gate but I didn't really see anyone.
Then I heard a rustle around the side of the house."
Nash nodded.
"That's right.
Somebody came around the house before you.
He - or she - hesitated by the window, then went on quickly - heard you, I expect."
I apologized again.
"What's the big idea?" I asked.
Nash said:
"I'm banking on the fact that an anonymous letter writer can't stop writing letters.
She may know it's dangerous, but she'll have to do it.
It's like a craving for drink or drugs."
I nodded.
"Now you see, Mr. Burton, I fancy whoever it is will want to keep the letters looking the same as much as possible.
She's got the cutout pages of that book, and can go on using letters and words cut out of them.
But the envelopes present a difficulty.
She'll want to type them on the same machine. She can't risk using another typewriter or her own handwriting."
"Do you really think she'll go on with the game?" I asked incredulously.
"Yes, I do. And I'll bet you anything you like she's full of confidence.
They're always vain as hell, these people!
Well, then, I figured out that whoever it was would come to the Institute after dark so as to get at the typewriter."
"Miss Ginch," I said.
"Maybe."
"You don't know yet?"
"I don't know."
"But you suspect?"
"Yes.
But somebody's very cunning, Mr. Burton.
Somebody knows all the tricks of the game."
I could imagine some of the network that Nash had spread abroad.
I had no doubt that every letter written by a suspect and posted or left by hand was immediately inspected.
Sooner or later the criminal would slip up, would grow careless.
For the third time I apologized for my zealous and unwanted presence.
"Oh, well," said Nash philosophically, "it can't be helped.
Better luck next time."
I went out into the night.
A dim figure was standing beside my car.
To my astonishment I recognized Megan.
"Hullo!" she said.
"I thought this was your car.
What have you been doing?"
"What are you doing is much more to the point?" I said.