Taking a street directory he began to go through the Gracechurch Street names, comparing each with the blot-sheet marks. He had been through about half when he came on one that seemed the correct shape—Messrs Moses Erckstein & Co. And when he saw that Messrs Erckstein were money-lenders, he felt hopeful that he was on the right track. But he was very thorough. He worked through the whole list, lest there should be some other name even more like that on the sheet. But there was none. Next morning he called on Messrs Erckstein. He was again wearing his silk hat and frock coat, and with these clothes he put on, to some extent at least, the manners of what our friends across the pond call a club man. He had made inquiries about the firm, and he now asked for the senior partner. After a delay of a few minutes he was shown into the latter’s room. Mr Erckstein was stout and dark, with a short black beard and Semitic features. Tanner had found out that, though he had been a German before the War, he was now a Pole. He proved an unwilling witness. It was not until Tanner had wasted over an hour, and threatened his informant with a summons to Court, where his books and his methods would be probed mercilessly in public, that he got what he required. Cosgrove Ponson, it appeared, was, and had been for many years, heavily in the firm’s debt. Including interest at the exorbitant rate charged, he now owed the money-lenders close on £30,000. Moreover, he had recently been severely pressed for part payment. Tanner, after a lot of trouble, saw copies of the letters sent, the last of which politely but unmistakably threatened proceedings and ruin unless the interest at least was immediately paid. ‘Why did you lend such a large sum?’ Tanner asked. ‘Because of his uncle, Mr Tanner. Sir William Ponson thought a lot of Mr Cosgrove, and he would have helped him. Now that he is dead we shall get our money. We understand Mr Cosgrove comes into a handsome legacy.’ When Tanner left the office he was more than satisfied as to the strength of Cosgrove’s motive for the crime. Far stronger it appeared to him than that of Austin. It looked as if he was on the right track at last. Hailing a taxi, he handed the driver a pound in advance and instructed him in detail as to what he wished done. Then he stepped into the vehicle and was driven to Knightsbridge. Within view of Cosgrove’s chambers the car swung close to the sidewalk and the engine stopped. The driver sprang down, and opening the bonnet, became engrossed with his engine. It was obvious a slight mishap had taken place. Tanner sat well back in the car watching the house before him. It was getting on towards one. For more than half an hour the repairs continued. Then the Inspector saw Cosgrove leave his door and hail a taxi. He called softly to his own driver, and the work at the engine being completed at just that moment, the latter mounted and started the car.