had stepped in, and whom they most likely believed to be the genuine Sir Gilbert Carstairs.  Put it this way:  once they’d found the documentary evidence they wanted, the particulars of Michael’s marriage, and so on, what had they to do but go to Sir Gilbert—­as they thought him to be—­and put it to him that, if he didn’t square them to keep silence, they’d reveal the truth to his nephew, whom, it’s evident, they’d already got to know of as Mr. Gavin Smeaton.  But as regards the actual murder of Phillips—­ah, that’s a mystery that, in my opinion, is not like to be solved!  The probability is that a meeting had been arranged with Sir Gilbert—­which means, of course, Meekin—­that night, and that Phillips was killed by him.  As to Crone—­it’s my opinion that Crone’s murder came out of Crone’s own greed and foolishness; he probably caught Meekin unawares, told what he knew, and paid the penalty.”

“There’s another possible theory about the Phillips murder,” remarked Mr. Gavin Smeaton.  “According to what you know, Mr. Elphinstone, this Meekin is a man who has travelled much abroad—­so had Phillips.  How do we know that when Meekin and Phillips met that night, Meekin wasn’t recognized by Phillips as Meekin—­and that Meekin accordingly had a double incentive to kill him?”

“Good!” exclaimed Mr. Lindsey.  “Capital theory!—­and probably the right one.  But,” he continued, rising and making for the door, “all the theories in the world won’t help us to lay hands on Meekin, and I’m going to see if Murray has made out anything from his search and his questioning.”

Murray had made out nothing.  There was nothing whatever in the private rooms of the supposed Sir Gilbert Carstairs and his wife to suggest any clue to their whereabouts:  the servants could tell nothing of their movements beyond what the police already knew.  Sir Gilbert had never been seen by any of them since the morning on which he went into Berwick to hear the case against Carter:  Lady Carstairs had not been seen since her departure from the house secretly, two mornings later.  Not one of all the many servants, men or women, could tell anything of their master or mistress, nor of any suspicious doings on the part of Hollins during the past two days, except that he had been away from the house a good deal.  Whatever share the butler had taken in these recent events, he had played his part skilfully.

So—­as it seemed—­there was nothing for it but to look further away, the impression of the police being that Meekin had escaped in one direction and his wife in another, and that it had been their plan that Hollins should foregather with them somewhere on the Continent; and presently we all left Hathercleugh House to go back to Berwick.  As we crossed the threshold, Mr. Lindsey turned to Mr. Gavin Smeaton with a shrewd smile.

“The next time you step across here, sir, it’ll be as Sir Gavin Carstairs!” he said.  “And we’ll hope that’ll not long be delayed!”