the detective who had spent so much of his life sharpening his wits
on the more intricate problems of crime.

When Guerchard came to the end of his questions, the Duke said: "You
have given me a very strong feeling that it is going to be a deuce
of a job to catch Lupin. I don't wonder that, so far, you have none
of you laid hands on him."

"But we have!" cried Guerchard quickly. "Twice Ganimard has caught
him. Once he had him in prison, and actually brought him to trial.
Lupin became another man, and was let go from the very dock."

"Really? It sounds absolutely amazing," said the Duke.

"And then, in the affair of the Blue Diamond, Ganimard caught him
again. He has his weakness, Lupin--it's women. It's a very common
weakness in these masters of crime. Ganimard and Holmlock Shears, in
that affair, got the better of him by using his love for a woman--
'the fair-haired lady,' she was called--to nab him."

"A shabby trick," said the Duke.

"Shabby?" said Guerchard in a tone of utter wonder. "How can
anything be shabby in the case of a rogue like this?"

"Perhaps not--perhaps not--still--" said the Duke, and stopped.

The expression of wonder faded from Guerchard's face, and he went
on, "Well, Holmlock Shears recovered the Blue Diamond, and Ganimard
nabbed Lupin. He held him for ten minutes, then Lupin escaped."