He liked casinos because of the money. You could see it in casinos, you could breathe it, smell it, hear it, touch it, and you could even taste it in the air. That taste was more delicious than any food he had ever eaten. Money brought you freedom, power. The ability to do something about your life and your family’s life.

It had given Cosmescu the ability to take his handicapped sister, Lenuta, out of a camin spital, a state home-hospital tucked away in the village of Plataresti, twenty-five miles north-east of Bucharest, and into a beautiful home in hills above Montreux in Switzerland, overlooking Lake Geneva.

When he had first seen her, ten years ago, after a lot of enquiries and a lot of bribes to find her, she was classed as an irrecupable. She was lying in an old, caged cot, eleven years old, eating only milk and crushed grain. With her skeletal figure and pot belly from starvation, and ragged strip of cloth as a nappy, she looked like a victim in a concentration camp.

There were thirty cots in that cramped room, with vertical bars, side by side and jammed next to each other, like animal cages in a laboratory. The stench of vomit and diarrhoea was overpowering. He watched stronger children, all retarded in some way, all still on the same bottled milk with crushed grain, despite the fact that some were in their mid-teens, if not older, swigging their liquid food then sticking their arms through the bars of their cages and taking the bottles from the younger, weaker ones – and being ignored by the solitary carer, who sat in her office, unqualified and unable to cope.

As the ball rattled over the metal slots of the wheel again, Cosmescu’s mobile phone, on silent, vibrated. He slipped it out of his pocket, at the same time clocking the winning number, 19. Shit. That was a bad number for him, a total loss on that one. He moved a short distance from the table, entering the number with his toes, and looked at the display. It was a text from the sef.

Want to speak right now.

Cosmescu slipped out of the casino and crossed the car park, making his way towards the Wetherspoon’s pub, where he knew there was a payphone downstairs. When he reached it, he texted its number on his mobile phone, then waited. Less than a minute later, it rang. It was noisy in the packed pub and he had to hold the phone close to his ear.

‘Yes?’ he said.

‘You’ve screwed up,’ the voice at the other end said. ‘Big time.’

Cosmescu talked for several minutes before returning to his table at the casino. When he did so, his concentration was gone. His losses increased, passing his limit, growing to £2,300 and then £2,500. But instead of stopping, anger drove him. Anger and gambler’s folly.

By twenty past three in the morning, when he finally decided to call it quits, he was just over £5,000 down. His worst loss ever on a single night.

Despite that, he still tipped the coat-check girl and the valet-parking guy their regular, crisp, fresh £10 note each.

Roy Grace, dressed in his tracksuit, baseball cap and jogging shoes, let himself out of Cleo’s front door just before half past five. In the glow of the street lights, the pre-dawn darkness was an amber mist and a cold wind blew salty drizzle on to his face.

He was burning with excitement and had barely slept, thinking about Cleo and the baby growing inside her. It was an incredible feeling. If he had been asked to put it into words he could not, at this moment, have done so. He felt a strange sense of empowerment, or responsibility, and, for the first time in his career, a shift in his priorities.

He walked across the yard and let himself out of the gate, glancing up and down the street, checking for anything that might look wrong. Every police officer he had ever met was the same. After a few years of being in the force you automatically clocked everything around you, constantly, whether you were in a street, a shop or a restaurant. Grace jokingly called it a healthy culture of suspicion, and there were plenty of times in his career when that had served him well.

As he set off on this late November Thursday morning, feeling more protective of Cleo than ever, nothing he saw on the deserted streets of Brighton aroused any suspicion in him. Ignoring the pain in his back and ribs from his car roll-over, he ran along the narrow pedestrianized cobbles of Kensington Gardens, past its cafés and boutiques, a second-hand furniture store and an antiques and bric-à-brac market, then along Gardner Street, past Luigi’s, one of the shops where Glenn Branson, his self-appointed style guru, insisted on taking him from time to time to spruce up his wardrobe.

As he reached deserted North Street, he saw headlights and heard the roar of a powerful engine. Moments later a black Mercedes SL sports coupé flashed past, its driver barely visible through the darkened windows. A tall, lean male figure was the sense of him that Grace got, but that was all. He wondered what the man was doing out at this hour. Returning from a party? Rushing to a ferry port or airport? You didn’t see many expensive cars this early in the morning. Mostly it was the cheaper cars and vans of manual workers. There were, of course, any number of legitimate reasons why the Mercedes would be on the road, but all the same he memorized the number: GX57 CKL.

Crossing over, he ran on through the narrow streets and alleys of the Lanes and then finally reached the seafront promenade. It was deserted except for a solitary man walking an elderly, plump dachshund. Limping less as he warmed up, he ran down the ramp, past the front of a large nightclub, the Honey Club, which was dark and silent, then stopped for some moments and touched his toes several times. Then he stood still, breathing in the tangs of the beach, of salt, oil, putrid fish, boat varnish and rotting weed, listening to the roar and sucking of the sea. The drizzle felt like cooling spray against his face.

This was one of the places he loved most in the city, down at sea level. Especially now, early morning, when it was deserted. The sea had a hold on him. He loved all of its sounds, smells, colours and changing moods; and especially the mysteries it contained, the secrets it sometimes yielded, such as the body last night. He could never imagine living somewhere landlocked, miles away from the sea.

The Palace Pier, one of the great landmarks of the city, was still lit up. New owners had changed its name to Brighton Pier a few years back, but to him and to thousands in the city it would always be the Palace Pier. Tens of thousands of bulbs burned along its length, along the rooftops of its structures, making the helter-skelter look like a beacon rising into the sky, and he wondered, suddenly, how long it would be before the pier was obliged to switch everything off at night to save energy.

He turned left and ran towards it, and then into the shadows beneath its dark, girdered mass – the place where, twenty years ago, he and Sandy had had their first kiss. Would his child one day kiss his – or her – first date here too, he wondered, as he emerged on the far side. He covered a further half-mile, then headed back to Cleo’s house. A short circuit today, just over twenty minutes, but it left him feeling refreshed and energized.

Cleo and Humphrey were still asleep. He had a quick shower, microwaved the bowl of porridge Cleo had left out for him, gulped it down while flicking through the pages of yesterday’s Argus, then headed off to the office, pulling into his parking space at the front of Sussex House, the CID headquarters, at a quarter to seven.

If he didn’t get interrupted, he would have a clear hour and a half to deal with his overnight emails and the most urgent of the paperwork before heading to the mortuary for the post-mortem on the Unknown Male, as the body hauled up by the dredger was named at this moment.