It was obvious to him that, if true, Cosgrove’s story made a complete alibi. If he had been at King’s Cross at 7.30 o’clock, at the Follies Theatre at 9.30, and had travelled from King’s Cross to Montrose by the 10.30 express it was out of the question that he could have been at Luce Manor. Satisfied as Tanner was as to the soundness of Austin Ponson’s alibi, Cosgrove’s was even more convincing, and what was better still, it would be easier to test. Though he did not believe Cosgrove would make such a statement unless it could bear the touchstone of inquiry, Tanner felt his obvious next business would be to check what he had just heard so fully as to remove all possible doubt of Cosgrove’s innocence. CHAPTER VII. Cosgrove’s Trip North On leaving Cosgrove Ponson, Inspector Tanner walked slowly up the shady side of Regent Street, his mind still running on the statement to which he had just listened. To test its truth was his obvious first duty, and as he sauntered along he considered the quickest and most thorough means of doing so. From the very nature of the story he felt inclined to believe it. Too much independent testimony seemed to be available for the alibi to be a fraud. And if this was so, he, Tanner, was on the wrong track, and was wasting time. He had already lost nearly a week over Austin, and all the time he was working on these blind alleys the real scent was getting cold. But as he reviewed the facts he had learnt, he felt he could hardly have acted otherwise than as he had. He considered Cosgrove’s statement point by point. Firstly, was it true he could only have gone to Scotland on the night in question of all others? In answer to this it should be easy to find out if he really was at the Duchess of Frothingham’s on the same afternoon. Then the missing of the train at King’s Cross must be known to several persons—the clerk at the stationmaster’s office, the barmaid who sold the cigars, as well possibly as the sleeping-car attendant, and the telegraph-office clerk, and copies of the wires to Grantham and to Montrose should be available. He was not sure that confirmation of Cosgrove’s visit to the Empire would be obtainable, though some attendant might have noticed him. But there should be ample proof of his call on Miss Belcher at the Follies Theatre. Not only would there be the testimony of Miss Belcher herself, but some of the many attendants must almost certainly have seen him. Then, if Cosgrove was not actually seen leaving London by the 10.30 p.m., he must have been observed in that train at Grantham, where his luggage was handed in to him. Finally, to ensure that he did not leave the train there and return to Luce Manor, as well as to test the genuineness of the whole journey, Tanner could see Colonel Archdale, the horse owner of Montrose.