The first driver said he had been hailed by a man of the description in question about 10.0 a.m. on Tuesday of last week. The fare had explained that he wished to engage his vehicle up till one o’clock. He was a traveller in precious stones and he wished to be taken to certain jewellers of which he had a list. The taximan had done as he was asked. Starting near the Marble Arch, he had visited one jeweller after another during the whole morning. Shortly after one the fare had instructed him to drive to Marylebone Station, which was then close by. There the taxi had been paid off, the fare disappearing into the station.

Asked if he could remember all the shops he called at, the man said he thought he could, and French at once despatched Sergeant Carter with him to drive over the same ground and make inquiries en route.

The second taximan had a very similar story to tell. About three o’clock on the Thursday afternoon he was driving slowly down Aldwych, when he was hailed by a man of the description the sergeant had given him. The man had engaged him by the hour and had told him of his business in precious stones and they had driven to a number of jewellers, ending up about five-thirty at Malseed’s, in the Strand. There the man had paid him off and he had seen him entering the shop as he drove away.

This driver also said he could remember the places at which he had called, and French sent another of his satellites round with him to amass information.

As far as it went, this was satisfactory enough. If the other taximen could be found, every minute of Roper’s three days would soon be accounted for. And it would be a strange thing if amongst all those with whom he had come in contact, some one person had not learnt or noticed anything which would help to find him. French could recall many instances where a chance recollection of some physical peculiarity, of some word or phrase uttered, of some paper or small article dropped, had led to the identification of a criminal and he thought the chances of similar good fortune in the present instance were not too remote.

All through the afternoon information continued to come in, and when he had added the items to his skeleton time-table he found that he had learnt where thirty-one rings had been bought and where Roper had lunched on each of the three days in question. Of course, this information did not directly help with his present problem, but there were two other items of news which seemed more promising.

The first was that seven of the thirty-one shop assistants who had been interviewed had noticed a fresh cut on Roper’s thumb, small, but peculiarly shaped. This was an additional identification which might be useful in dealing with waiters, dining-car attendants, hotel porters and others who would be likely to observe a customer’s hand.

The second item French received with deep satisfaction. Roper had spent the Tuesday night at the Strand Palace Hotel. This seemed to negative the suggestion that the man was living in London, and French therefore became much more hopeful of the prospects of finding his whereabouts on the Thursday night, the point at which he must start if he was to succeed in tracing him.

But it was not until the next afternoon that his hopes were fulfilled. When he reached the Yard after lunch he found that a telephone message had just been received from Sergeant Elliott, who was working the hotels in the Bloomsbury area. Roper, the man reported, had spent the Thursday night at the Peveril Hotel in Russell Square.

Within twenty minutes French had reached the building. Sergeant Elliott was waiting for him in the lounge.