Burnley complied, explaining in half a dozen sentences the gist of the case.

‘The circumstances are certainly singular,’ said the Chief. ‘Let me think whom I shall put in charge of it with you. Dupont is perhaps the best man, but he is engaged on that burglary at Chartres.’ He looked up a card index. ‘Of those disengaged, the best perhaps are Cambon, Lefarge, and Bontemps. All good men.’

He stretched out his hand to the desk telephone.

‘Pardon me, sir,’ said Burnley. ‘I don’t want to make suggestions or interfere in what is not my business, but I had the pleasure of co-operating with M. Lefarge in the Marcelle case, and if it was quite the same I should very much like to work with him again.’

‘But excellent, monsieur. I hear you say that with much pleasure.’

He lifted his desk telephone, pressing one of the many buttons on its stand.

‘Ask M. Lefarge to come here at once.’

In a few seconds a tall, clean-shaven, rather English looking man entered.

‘Ah, Lefarge,’ said the Chief. ‘Here is a friend of yours.’

The two detectives shook hands warmly.