He had left the hotel in an ordinary taxicab, which had stopped on the way to pick up no other passenger.

He had left the Savoy alone, and he was discovered in Melbourne Square alone.

Yet, somewhere between these two points, notwithstanding the fact that the aggressor must have entered the cab either with or without his consent, Mr.Richard Vanderpole, without a struggle, without any cry sufficiently loud to reach the driver or attract the attention of any passer-by, had been strangled to death by a person who had disappeared as though from the face of the earth.

The facts seemed almost unbelievable, and yet they were facts.

The driver of the taxi knew only that three times during the course of his drive he had been caught in a block and had had to wait for a few seconds--once at the entrance to Trafalgar Square, again at the junction of Haymarket and Pall Mall, and, for a third time, opposite the Hyde Park Hotel.