However quietly she might have behaved in the landlady's previous experience of her, she was beside herself now.

I might have been moved by a natural pity for her, or I might have been completely upset in my mind--I only know this, I could not persuade myself that she was guilty.

I even said to Mrs.Crosscapel, "I don't believe she did it." While I spoke there was a knock at the door.

I went downstairs at once, and admitted (to my great relief) the Inspector, accompanied by one of our men.
He waited downstairs to hear my report, and he approved of what I had done.

"It looks as if the murder had been committed by somebody in the house." Saying this, he left the man below, and went up with me to the second floor.
Before he had been a minute in the room, he discovered an object which had escaped my observation.
It was the knife that had done the deed.
The doctor had found it left in the body--had withdrawn it to probe the wound--and had laid it on the bedside table.