"And have you found out anything about them?" he asked Mr. Coburn.

"Only what I have been able to pick up from their own conversation,"
the manager answered. "I wrote Morton asking him to make inquiries
about them, but of course there hasn't been time yet for a reply.
>From their own showing one of them is Seymour Merriman, junior
partner of Edwards & Merriman, Gracechurch Street, Wine Merchants.
That's the dark, square-faced one - the one who was here before.
The other is a man called Hilliard. He is a clever fellow, and holds
a good position in the Customs Department. He has had this launch
for some years, and apparently has done the same kind of trip through
the Continental rivers on previous holidays. But I could not find
out whether Merriman had ever accompanied him before."

"But you don't think they smell a rat?"

"I don't think so," he said slowly, "but I'm not at all sure.
Merriman, we believe, noticed the number plate that day. I told you,
you remember. Henri is sure that he did, and Madeleine thinks so
too. It's just a little queer his coming back. But I'll swear
they've seen nothing suspicious this time."

"You can't yourself account for his coming back?"

Again Mr. Coburn hesitated.

"Not with any certainty," he said at last, then with a grimace he
continued: "But I'm a little afraid that it's perhaps Madeleine."

Bulla, the engineer, made a sudden gesture.