Peter considered.
"A double cross is often a very pretty thing," he admitted, "but I've seen too many examples among the police of digging a pit and falling in themselves. One difficulty is that we don't want to alarm Albert more than necessary. At present he only knows that I think him in danger; but he has not the most shadowy idea that members of his own household are implicated. He won't know it till I forbid him to touch his breakfast. Yes; we can certainly try a double cross. He shall order bread and milk—we know who will bring it to him. Then his cat, 'Grillo,' shall breakfast upon it." Peter turned to Mark. "That will convince you, my friend."
But the other shook his head.
"It depends upon circumstances. Even granted poison, many an honest man and woman has been the innocent tool of a murderer's will."
"True enough; but we are wasting time upon an improbability. I do not myself think it will be attempted. It is the line of least resistance and the line of least resistance generally means the lines of greatest risk afterward. No—he'll do something smarter than that if he gets half a chance. The grand danger would be that Doria should find himself alone with Albert, even for a moment. That is the situation to circumvent and avoid at any cost. Let nothing induce you to lose sight of one or other; and even should Doria obviously make a run for it before I return, don't be deceived by that, or go after him. He may adopt any ruse to get you guessing when I have gone—that is, if he suspects me of some immediate step. But if I go without leading him to feel any very grave suspicion as to my object in going, we may surprise him before his own stroke is struck. That, in a word, is our objective."
An hour later the detectives saw Signor Poggi to his boat and then walked home with Mr. Redmayne. Peter had provender concealed about his person and presently he explained to his friend that things were now come to a climax.
"In twenty-four hours I hope we're through with our mysteries and plots, Albert," he said; "but during that time you've got to obey me in every particular and so help me to set you free from this abomination hanging over you. I can trust you; and you must trust me and Mark here till to-morrow night. You'll soon be at peace again with your troubles ended."
Albert thanked Ganns and expressed his satisfaction that a conclusion was in sight.
"I have seen through the glass darkly," he told them. "Indeed I cannot say that I have seen through the glass at all. I am entirely mystified and shall be glad indeed to know this horror with which I am threatened may be removed. Only my absolute trust in you, dear Peter, has prevented me from becoming distracted."
At the villa Brendon left them and Jenny welcomed her uncle. The girl begged Mark to come in for a while before returning; but it was late and Mr. Ganns declared that everybody must retire.