'Did you take up a passenger a few minutes past three o'clock on the Boulevard des Italiens, near the Crédit-Lyonnais? Had he a short black beard? Did he carry a small box in his hand and order you to drive to the Madeleine?'

The cabman seemed puzzled.

'He wore a short black beard when he got out of the cab,' he replied.

'What do you mean by that?'

'I drive a closed cab, sir. When he got in he was a smooth-faced gentleman; when he got out he wore a short black beard.'

'Was he a Frenchman?'

'No, sir; he was a foreigner, either English or American.'

'Was he carrying a box?'

'No, sir; he held in his hand a small leather bag.'

'Where did he tell you to drive?'