He remembered that he had already learnt the trains by which the murdered man had travelled to town. He could thus start with the practical certainty that Sir William had arrived at St Pancras at 11.40 on the Saturday and the Monday before the crime. By what means would the deceased leave the station? Tanner did not think a man of his position would walk or go by bus or tube. No, as his private car was not available he would take a taxi. ‘I must find the man who drove him,’ the Inspector thought. He gave his bell a code ring, and instructed the assistant who answered to undertake the inquiry. From the constables on station duty the numbers of the vehicles which left on the arrival of the train in question could be obtained, and it would be a simple matter to find the drivers and learn by means of a photograph which of them had driven Sir William, and to what point. But Tanner was by no means sanguine that such an inquiry would bear fruit. He believed that the deceased had not used his own car because he wished to cover his traces. And if so he would probably have avoided taking a taxi at the station. It would have been safer for him to have picked one up in the street outside. Tanner therefore felt he should if possible have another string to his bow. Where could such be found? A second line of inquiry soon suggested itself. Sir William would not have passed the day without food. If Tanner could find where he lunched, it would give him another point of attack. The Inspector had learned from Innes his master’s usual restaurants, as well as the names of his two clubs. As all these were extremely expensive and exclusive, Tanner felt he might confine his researches to places of the same type. He began at once. Driving to the first club, he made exhaustive inquiries. Sir William was a well-known figure there, and his death had caused some of the attendants to recall in conversation the occasion of his last visit. But this had been three weeks before the murder. The men were positive he had not been there either the Saturday or Monday in question. At the second club Tanner received similar information. Here Sir William had not been seen for over two months prior to his death. The Inspector then began on the restaurants. By the time he had visited the Carlton, the Savoy, and one or two others it was after eight o’clock. He therefore gave up for the night and, going home, busied himself in making out a list of other possible places at which he would inquire on the following day. Next morning he was early at work. He was very thorough and painstaking, leaving no restaurant till he had interviewed every one who might conceivably help him, from the manager down to the cloakroom attendant. For a long time he had no luck. But at last in the late afternoon, when he had worked half down his list and visited no less than seventeen restaurants, he found what he wanted.