Naball's suspicions were now rapidly ripening to certainties. If Malton were innocent, why these signs of agitation? He wriggled and twisted about like an eel, yet never once met the keen eye of the detective.
"You'd better remember," said Naball mercilessly, "or it will be the worse for you."
"Why?" asked Malton, trying to appear composed.
"Because," explained Naball, in a low voice, "that note is one of those stolen by the man who murdered Jacob Lazarus."
Malton, with a smothered exclamation, started to his feet, and then, shaking in every limb, sat down again.
"No, no," he stammered, "that's absurd. It can't be--I tell you, it can't be."
"Oh, but it can be, and it is. I tell you, the note is endorsed 'Back Flat-Iron,' which was done by the office-boy a few moments before the notes were put in the safe by Stewart. They were gone after the murder, so there is no doubt they were taken by the man who committed the crime. I got this note from Miss Rainsford, who received it from Caprice; she, in her turn, got it from Mortimer, and he has referred us to you. Now, where did you get it?"
Malton drummed nervously on the table.
"I can't tell you," he said in a tremulous voice.
"You must."