‘We did a big line with Interpol and the appropriate countries but although they were dead keen they weren’t all that much of a help. Throughout his lamentable career the Jampot had only made one blunder: and that, as far as we could ferret it out, was because an associate at the Bolivian end of his drug racket had grassed. The associate was found dead by quick attack from behind on the carotids: the method that Foljambe had certainly employed in Paris and was later to employ upon the wretched Andropulos. But for reasons about which the Bolivian police were uncommonly cagey, the Jampot was not accused by them of murder but of smuggling. Bribery is a little word we are not supposed to use when in communication with our brothers in anti-crime.

‘It’s worth noticing that whereas other big-shots in his world employ their staffs of salaried killers the Jampot believes in the do-it-yourself kit and is unique in this as in many other respects.

‘Apart from routine field-work the immediate task, as I saw it, was to lay out the bits of information as provided by my wife and try to discover which fitted and which were extraneous. I suggest that you treat yourselves to the same exercise.’

The man in the second row could almost be seen to lay back his ears.

‘We found nothing to help us on deck,’ continued Alleyn. ‘Her mattress had been deflated and stowed away and so had her blankets and the deck had been hosed down in the normal course of routine.

‘But the tow-path and adjacent terrain turned up a show of colour. At the Crossdyke end, and you’ll remember it was during the night at Crossdyke that the murdered woman disappeared, Mr Fox’s party found on the riverbank at the site of the Zodiac’s moorings, a number of indentations, made either by a woman’s cuban heel or those of the kind of “gear” boots currently fashionable in Carnaby Street. They overlapped and their general type and characteristics suggested that the wearer had moved forwards with ease and then backwards under a heavy load. Here’s a blow-up of Detective-Sergeant Thompson’s photographs.

‘There had either been some attempt to flatten these marks or else a heavy object had been dragged across them at right angles to the riverbank.