Together, they looked up the Tephi’s history. Old photographs filled the screen, of a huge cargo ship, heavily laden.

‘She’s a Panamax,’ read Ed. ‘That’s the biggest ship that can fit through the Panama Canal.’

Casey glanced at him, mouth turning up. ‘Geek.’

‘It’s true.’ He nudged her away. ‘There are others too. The Suezmax, which just fits down the Suez Canal. The Q-Max, that’s the biggest sort of vessel that can get in and out of Qatar. The Seawaymax, for getting down the Saint Lawrence Seaway into the Great Lakes in America.’

‘All right,’ Casey was laughing. ‘I get it.’

They looked at the photographs of the Tephi, huge and blue, piled high with containers like Lego blocks. A distinctive red stripe had been painted all the way around her hull, a few feet below her decks. Below her waterline she was a dark forest-green. In the photographs, the green showed through as she battled through waves. Shipping enthusiasts had snapped her in Guangzhou and in Rotterdam, in Long Beach and in Mombasa, loaded with containers filled with new cars or bright dresses, toothpaste or prams.

‘She’s certainly notched up the miles,’ said Casey.

She thought of the old ship, slapped over the nose with champagne at the start of her journeys, now trapped in the mud of Chittagong, her knickers showing shamefully.

‘The shipping companies sell them off when they get too old,’ she explained to Ed. ‘To the highest bidder. Cash buyers, usually, who sell them on straight away. The shipping companies know full well that the ships will end up in the wrecking yards of Bangladesh, but what do they care? They shrug their shoulders and say, “Gosh, we had no idea” when it emerges that their old ships are being disembowelled by eight-year-olds.’

‘A couple of steps removed,’ said Ed. ‘Deniable.’

‘It’s simple maths.’ Casey was nodding. ‘If you have your ship taken apart somewhere in Europe, you have to pay the scrapyard to do it carefully. In Bangladesh, they pay almost three hundred dollars a tonne for the steel.’

‘Who,’ said Ed, ‘could possibly say no?’

‘So this Jeetu character, who we think works closely with Dylan and Raz, bought up the Tephi,’ Casey said, ‘when she was on her last journey, and had her brought up to Chittagong.’

‘Jeetu might have been talking to Dylan or Raz when Jamalida overheard him, for all we know,’ said Ed.

The Tephi’s last movements had been small, edging to and fro just off the coast.

‘Parked up, waiting for the tide,’ Ed said. ‘They wait for the highest tide, to get the ships as far up the beach as possible. It makes the breaking easier if it’s not wallowing in water.’

‘So wherever the Tephi is now,’ Casey was thinking aloud, ‘Dylan and his team are likely to have some sort of base. We need to look there.’