The murder at the Villa Rose and the mystery which hid its perpetration had aroused interest.  This new development had quickened it.  From the balcony Hanaud could see the groups thickening about the boy and the white sheets of the newspapers in the hands of passers-by.

“Every one in Geneva or near Geneva will know of this message by now.”

“Who could have told?” asked Ricardo blankly, and Hanaud laughed in his face, but laughed without any merriment.

“At last!” he cried, as the waiter brought the bill, and just as he had paid it the light of a match flared up under the trees.

“The signal!” said Lemerre.

“Not too quickly,” whispered Hanaud.

With as much unconcern as each could counterfeit, the three men descended the stairs and crossed the road.  Under the trees a fourth man joined them—­he who had lighted his pipe.

“The coachman, Hippolyte,” he whispered, “bought an evening paper at the front door of the house from a boy who came down the street shouting the news.  The coachman ran back into the house.”

“When was this?” asked Lemerre.

The man pointed to a lad who leaned against the balustrade above the lake, hot and panting for breath.

“He came on his bicycle.  He has just arrived.”

“Follow me,” said Lemerre.

Six yards from where they stood a couple of steps led down from the embankment on to a wooden landing-stage, where boats were moored.  Lemerre, followed by the others, walked briskly down on to the landing-stage.  An electric launch was waiting.  It had an awning and was of the usual type which one hires at Geneva.  There were two sergeants in plain clothes on board, and a third man, whom Ricardo recognised.

“That is the man who found out in whose shop the cord was bought,” he said to Hanaud.

“Yes, it is Durette.  He has been here since yesterday.”

Lemerre and the three who followed him stepped into it, and it backed away from the stage and, turning, sped swiftly outwards from Geneva.  The gay lights of the shops and the restaurants were left behind, the cool darkness enveloped them; a light breeze blew over the lake, a trail of white and tumbled water lengthened out behind and overhead, in a sky of deepest blue, the bright stars shone like gold.

“If only we are in time!” said Hanaud, catching his breath.

“Yes,” answered Lemerre; and in both their voices there was a strange note of gravity.

Lemerre gave a signal after a while, and the boat turned to the shore and reduced its speed.  They had passed the big villas.  On the bank the gardens of houses—­narrow, long gardens of a street of small houses—­reached down to the lake, and to almost each garden there was a rickety landing-stage of wood projecting into the lake.  Again Lemerre gave a signal, and the boat’s speed was so much reduced that not a sound of its coming could be heard.  It moved over the water like a shadow, with not so much as a curl of white at its bows.