“No time like the present, though, is there?” said Mallett, unrebuffed. “I tell you what—I’m due at the Yard. If you’re not doing anything, why not share a taxi down there? We can have a little chat as we go.”

The smart umbrella was waved in the air, and a cab drew up at the pavement. Mallett flung open the door for Harper to get in. Harper hesitated a moment, looked up into the inspector’s still smiling face, then nodded abruptly and climbed into the vehicle. The door closed and the taxi moved off. A young reporter on an evening paper happened to see them go.

“Did you see that?” he said to a friend. “Inspector Mallett! He’s made an arrest!”

But it was Sergeant Frant, not Inspector Mallett, who was to make an arrest that day. His incessant labours had borne fruit. They had, to begin with, brought about a considerable liveliness in a quiet part of Yorkshire, involving not only the police, but also doctors, clergymen, registrars and asylum officials. The enquiries that Mr. Elderson had made quietly and unofficially were repeated with thoroughness and such dispatch that about the time that Mallett was entering Bramston’s Inn, Frant, in a police car, was turning into Mount Street, bearing in his pocket a fateful slip of paper, signed by the chief magistrate at Bow Street. He was just in time to see Captain Eales, a small suitcase in his hand, emerge from a house door, and step into a taxi which was waiting for him. The cab gathered speed slowly, and with the police car in its wake, drove off. As Frant had anticipated, it took a northerly direction, and in due time it drew up outside a pleasant little detached house in St. John’s Wood. Frant gave a quiet order to his driver, and the car slowed down close to the kerb, just giving him time to alight so that he touched the pavement almost at the same moment as did his quarry, fifty yards ahead. Then it drove on, past the house, turned into a side street, reversed and awaited further orders, just out of sight.

Frant strolled towards Eales, his pulses quickening slightly with the uncontrollable excitement of the hunter. But the latter instead of paying the cab, as he had expected, walked straight up to the front door of the house, leaving his suitcase behind him in the waiting vehicle. The sergeant judged it wise to hold his hand. He allowed Eales to enter the house unmolested, walked on past him to the corner, turned and came slowly back. He had not proceeded far when Eales emerged once more from the house. On the steps he turned, and called out to someone behind him: “Mind you, this is the last time!” Frant caught a glimpse of Du Pine standing in the porch, could just distinguish the expressionless smile which greeted the words, and then the door closed.