“Do you mean, then,” the young man breathed in a voice hardly above a whisper, “that James was Ballantine?”

“I do. A fact,” added Mallett, “which is going to prove very inconvenient to a number of otherwise excellent alibis.”

There was silence between them as the car crossed the end of Trafalgar Square and sped along Whithall.

“Of course,” murmured Harper, “I always thought that couldn’t have been his tie. Nobody could have worn one that colour with those clothes. I wonder why he changed it.” He shivered and then seemed to rouse himself suddenly from his reflections. “I’ll get out here, if you don’t mind,” he said. “That is, unless you want——”

“That’s all right,” said the inspector. “You’ve told me all I wanted to know, and very interesting it was.”

He ordered the driver to stop, put Harper down, and drove on alone into New Scotland Yard. He was feeling in a genial mood, expansive and self-satisfied. The chase was almost at an end and he was about to reap the reward of his persistence and ingenuity. It did not occur to him to look back at his late companion. Had he done so, he would have seen him stand a moment irresolute on the pavement, and then go quickly to a public telephone box.

Mallett made his way at once to his office. As he entered it, he was overtaken by Frant, in a high state of excitement. He motioned him to come in.

“Well?” he asked.

“I arrested Eales this afternoon,” said the sergeant.

“Yes? Is that all?”

“And Du Pine half an hour later.”

The inspector smiled. “More bigamy?” he asked.

Frant shook his head. “You may laugh, sir,” he said, “but that charge of bigamy has worked like a charm.”

“I’m sure it has. But what exactly is Du Pine’s offence?”

“Drug-trafficking.”

“Aha! So that was his little game, was it?”

“Yes. He’d been importing it on quite a large scale for some time apparently, and latterly employing Eales as his messenger to Paris. The poor devil was so hard up he couldn’t refuse, he tells me, and he was quite well paid. When I arrested him this morning he was just off on another trip—by air this time.”

“The infernal cheek of that fellow Du Pine—right under our noses!”

“It was rather more than just cheek,” said the sergeant gently. “You see, he had to get the stuff—he wanted it, desperately.”

“For his own use, you mean?”