It was after nine when Plummer returned. The rector had just rejoined Hewitt in the study, having left poor Miss Creswick, utterly broken down, in her room, in charge of a scarcely less terrified servant. Plummer tapped, and pushed the study door open.
"That's done clean and sure enough," he said, with professional calmness. "And he's a cool hand, is that Dr. Lawson. But have you found anything more? We shall want all we can get."
"We shall," Hewitt assented, "and we shall find more than we've got now, or I'm grievously mistaken. But tell me first what you've done."
He removed the blotting pad, on which the paper ashes still lay, and very carefully shut it away in a wide drawer where no draught could disturb it; he also shut another drawer which stood open.
"We had no difficulty in finding Dr. Lawson," Plummer began. "We met him, in fact, leaving his surgery. I went back with him into the gas-light, and there put it to him plump. Well, he was staggered, badly. Any man would be, of course. But he pulled himself together wonderfully soon, and the first thing he said was that he was just on his way to Mason's house. I thought at first, of course, that he meant to deny that he had been there already, and I gave him the usual warning about what he said being used in evidence. But he went on, and I've got it all safely noted. He admitted that he had been here, at about seven o'clock or just before, and he said he came because Mr. Mason sent for him. That doesn't seem likely, does it, on the facts as we know them?"
"Why, no," said the rector. "The last time he was here he was ordered out, and I know of no reason why he should have been asked to come to-day. We must ask if anybody was sent."
"I have asked," replied Plummer, "just now, and none of the servants was sent. But Lawson's story is that he was sent for and came, though he said he shouldn't say what Mason wanted to see him about till he knew more of the case. Looks as though he hadn't quite got his story ready yet, doesn't it? He had thought over the point about not being seen to go away, though; he said he had let himself out at about half-past seven, being familiar with the ways of the house. And he said that Mason was rather unwell—nervously upset—when he left him, but that was all."
"It's terrible," said the rector, "terrible. It seems impossible to believe it of young Lawson; and yet—and yet!" And then after a pause—"Good heavens!" he burst out again. "Why, I only realise it now! There is the other crime, too! Denson! Two murders! Two—and most certainly by the same hand! Mr. Plummer, I can't believe it! Oh, there's more behind, more behind, Mr. Hewitt."
"There is more," said Hewitt, "as you will see when I tell you the little I have been able to ascertain. There is more behind, though I see little of it yet. First——"
There was a sharp knock at the front door, followed by a ring, muffled in the distant kitchen. Hewitt started up. "Who is this late visitor at this unvisited house?" he said. "If it is the police, well enough. But if anybody else—anybody—you may call me Doctor, or anything you please, except Martin Hewitt. Don't forget that!"