It was known later that, in spite of the keen hunt after him by the most expert of detectives, he had sat that same evening at a first performance in the Theatre Francais, without the slightest disguise.
He left France, later, to "work" America.

The police there succeeded in capturing him once, but the extraordinary man escaped the next day.

It would need a volume to recount the adventures of this master-criminal.
And yet this was the man Rouletabille had allowed to get away! Knowing all about him and who he was, he afforded the criminal an opportunity for another laugh at the society he had defied! I could not help admiring the bold stroke of the young journalist, because I felt certain his motive had been to protect both Mademoiselle Stangerson and rid Darzac of an enemy at the same time.
The crowd had barely recovered from the effect of the astonishing revelation when the hearing was resumed.

The question in everybody's mind was: Admitting that Larsan was the murderer, how did he get out of The Yellow Room?
Rouletabille was immediately called to the bar and his examination continued.
"You have told us," said the President, "that it was impossible to escape from the end of the court.

Since Larsan was leaning out of his window, he had left the court.