Having purchased a butterfly net he returned to the hotel and dressed. When his toilet was complete, he looked at himself in a glass and felt satisfied.

He looked, in fact, like a shopboy whose taste for entomology had devoured his taste in dress.

Smug and plump, you never would have suspected this shopboy or café waiter out for a holiday, to be a detective destined to European fame. A chilly-blooded calculator, a profound thinker, with an intimate knowledge of all the most terrible abysses of crime. A man merciless and fearless as a sword.

An hour later, at the boat-slip just above the bridge, Freyberger stood bargaining for a boat.

It was a lovely day, soft and warm with a cloudless sky.

He was not a very good oarsman, but good enough to scull a boat safely on a smooth river. After he had passed the bridge and East’s boat-slip, he rested on his oars for a minute.

“If I had not questioned her imagination,” he said to himself, “that man Hellier would not have remembered those other crimes, and I would not have come near the bull’s-eye like this. How terribly right she was. She divined this devil, she knew his construction, his capacity for murder without a motive. She is an innocent woman, yet she knew this demon as well as if she had constructed him—sub-consciously. Ah, the sub-consciousness of women, what does it not hide? A woman who loves is a terrible thing, more keen-scented than a hound, more dangerous than a tiger.

“My friend, Klein, if I miss you here it will not be the fault of Mademoiselle Lefarge. If I miss you here, I shall find you again, but if I find you here, I will be the means of saving the lives of perhaps two more men, perhaps three.”

He resumed his sculls.

The warm weather had brought boats out as well as butterflies and butterfly-hunters, girls in summer dresses and men in flannels, who little dreamt that tragedy was passing them in the form of the little man in the mulberry-coloured coat.