He stopped the moment he saw me.
"You must be careful, policeman," he says.

"I found the man lying on his back, in bed, dead--with the knife that had killed him left sticking in the wound." Hearing this, I felt the necessity of sending at once to the station.
Where could I find a trustworthy messenger?
I took the liberty of asking the doctor if he would repeat to the police what he had already said to me.

The station was not much out of his way home.

He kindly granted my request.
The landlady (Mrs.Crosscapel) joined us while we were talking.

She was still a young woman; not easily frightened, as far as I could see, even by a murder in the house.