‘Probably by the taxi,’ suggested Daunt, and they returned to where the vehicle was waiting.

But his guess was incorrect. The driver assured them that on reaching the cross-roads Cosgrove had paid him off and he had returned at once to London.

‘I thought of that first,’ said Lois, ‘then I thought not, that he would never have let any one man have so much information about his movements. Then I wondered if he wouldn’t have arranged for a vehicle from Halford to pick him up, but I saw that wouldn’t do either. At last I thought the most obvious and indeed the least suspicious plan would be to engage a car in Hitchin to run out for him. What do you think?’

‘I believe you are right. Let’s run over to Hitchin now and make inquiries.’

They reached the town in about quarter of an hour. There they paid off their taxi, having noted the man’s name and address. Then after a hurried lunch they got to work.

At the first and second garages they drew blank, but at the third they had success. It appeared that late on the Monday evening before the murder, a man, whom the proprietor instantly identified from the photograph as Cosgrove, called and asked for a car to be sent to the same cross-roads near Luce Manor. It was to be there on the following Wednesday evening at 10.15, and was to wait for him and run him into Hitchin. He gave no explanation of his movements, but he turned up at the place a few minutes after the hour named, and was duly brought to Hitchin and set down near the George Hotel. Daunt had the driver sent for, and he stated he had seen his fare’s face in the light of a street lamp when he was being paid, and he also unhesitatingly selected Cosgrove’s photograph as that of the man.

‘How far is it from the George Hotel to the station?’ asked Daunt.

‘Three minutes’ walk, sir.’

Here at last was proof—utter and final proof. As the cousins left the garage Jimmy once more congratulated his companion on her success.

‘But we’re not finished yet, Jimmy,’ she answered him. ‘We have to find the woman—the false servant.’