Every morning, since my first visit to Estrella de Mar, I had driven from the Los Monteros Hotel, carrying out my detective investigation. I cancelled my TV assignment in Helsinki and telephoned my agent in London, Rodney Lewis, asking him to put all other commitments on hold.

'Does that mean you've found something?' he asked. 'Charles…?'

'No. I've found absolutely nothing.'

'But you think it's worth staying out there? The trial won't start for several months.'

'Even so. It's an unusual place.'

'So is Torquay. You must have some idea what happened?'

'No… to tell the truth, I haven't. I'll stay here, though.'

Nothing I had found gave me the slightest hint of why my brother, at home and at ease for the first time in his life, should have turned into an arsonist and murderer. But if Frank had not set fire to the Hollinger mansion, who had? I asked David Hennessy for a list of his fellow-guests at the party, but he refused point-blank, claiming that Inspector Cabrera might charge other guests with the crime if Frank withdrew his confession, and perhaps incriminate the entire community.

The Keswick sisters told me that they had attended the Queen's birthday parties for years. They had been standing by the pool when the flames erupted through the bedroom windows, and left with the first stampede of guests to their cars. Anthony Bevis, owner of the Cabo D'Ora Gallery and a close friend of Roger Sansom, claimed that he had tried to force the French window but had been driven back by the exploding tiles that were leaping from the roof. Colin Dew-hurst, manager of a bookshop in the Plaza Iglesias, had helped the Hollingers' chauffeur to carry a ladder from the garage, only to watch the upper rungs catch fire in the intense blaze.

None of them had seen Frank slip into the house with his lethal flagons of ether and petrol, or could conceive of any reason why he might want to kill the Hollingers. I noticed, however, that of the thirty people I questioned not one suggested any other suspect. Something told me that if his friends really believed in Frank's innocence they would have hinted at the identity of the true assassin.

Estrella de Mar seemed a place without shadows, its charms worn as openly as the bare breasts of the women of all ages who sunbathed at the Club Nautico. Secure on their handsome peninsula, the people of the resort were an example of the liberation that follows when continuous sunlight is shone on the British. I could understand why the residents were less than keen for me to write about their private paradise, and already I was beginning to see the town through their eyes. Once I had freed Frank from prison I would buy an apartment of my own and make it my winter base.

In many ways Estrella de Mar was the halcyon county-town England of the mythical 1930s, brought back to life and moved south into the sun. Here there were no gangs of bored teenagers, no deracinated suburbs where neighbours scarcely knew each other and their only civic loyalties were to the nearest hypermarket and DIY store. As everyone never tired of saying, Estrella de Mar was a true community, with schools for the French and British children, a thriving Anglican church and a local council of elected members which met at the Club Nautico. However modestly, a happier twentieth century had rediscovered itself in this corner of the Costa del Sol.

The only shadow cast across its plazas and avenues was the fire at the Hollinger house. In the late afternoon, when the sun moved behind the peninsula and set off towards Gibraltar, the silhouette of the gutted mansion crept along the palm-lined streets, darkening the pavements and the walls of the villas below, silently wrapping the town in its sombre shroud.

As I stood among the graves beside Elizabeth Shand, and waited for the casket of the young Swedish woman, it occurred to me that Frank might have pleaded guilty in order to save Estrella de Mar from being overrun by British and Spanish police, or by private detectives hired by relations of the Hollinger family. This innocence of crime might even explain the voyeuristic gaze of the people I had caught in the floodlights of the Club Nautico car park. Never having seen a rape, they had watched the assault as if it were some folkloric or pagan rite from a more primitive world.

One of the couples, I suspected, was present among the mourning party, a retired Bournemouth accountant and his sharp-eyed wife who ran a video-rental store in the Avenida Ortega. Both tried to avoid my camera lens and only relaxed when a black Cadillac hearse drew up outside the cemetery.

In Estrella de Mar death alone had been franchised to the Spanish. The pallbearers of the funeral firm in Benalmadena eased the polished casket from the hearse and transferred it to a cart manned by the cemetery staff. Preceded by the Reverend Davis, the pale and earnest vicar of the Anglican church, the cart rumbled towards the waiting grave. The clergyman's eyes were fixed on the grating wheels, teeth gritted against the painful sounds. He seemed embarrassed and uneasy, as if in some way holding the mourners responsible for the Swedish girl's death.

Stiletto heels teetered on the stony ground as everyone stepped forward. Heads were lowered, eyes avoiding the coffin and the hungry vault that would soon embrace it. Only Gunnar Andersson watched as it sank jerkily from sight, fed into the ground by the gravediggers' tapes. Tears gleamed through the faint beard on his sallow cheeks. His long legs straddled the heap of damp soil when the men reached for their spades, delaying the interment to the last moment.

A few feet from him Dr Sanger was staring at the coffin. His slim chest inflated at ten-second intervals, as if he were unconsciously starving himself of air. He smiled in a tender but almost remote way, like the owner of a dead pet briefly remembering their happier days together. He picked a handful of soil from the ground and threw it on to the coffin, then ran his hand through his shock of blow-dried hair, leaving a few grains of sand in the silvery waves.

The Reverend Davis was about to speak, but waited for a group of late arrivals who had entered the cemetery. David Hennessy led the way, nodding to the mourners as he carried out a quick head-count and confirmed that everyone he had notified was present, glad to lend his special skills to that even larger club than the Nautico, with its unlimited membership and no waiting list.

Behind him, face hidden by a silk scarf, was Dr Paula Hamilton, the dark-haired swimmer I had seen soon after my arrival. A resident physician at the Princess Margaret Clinic, she was one of the few people who had declined to talk to me. She had failed to return my telephone calls, and refused to see me at her office in the Clinic. Now she seemed as reluctant to attend the burial service, standing behind Hennessy with her eyes fixed on his heels.

Bobby Crawford, the Club Nautico's tennis professional, followed her from the gate. Dressed in a black silk suit and tie, sunglasses over his eyes, he resembled a handsome and affable gangster. He greeted the mourners with a reassuring wave, his outstretched hands touching a shoulder here and patting an arm there. Everyone seemed to revive in his presence, and even Elizabeth Shand raised the brim of her new straw hat to beam at him maternally, lips fleshing as she murmured sleekly to herself.

The Reverend Davis completed his perfunctory address, never once meeting the mourners' eyes and clearly eager to be back with his parish. Stones rattled on the coffin lid as the gravediggers spaded the heavy soil into the grave, shoulders bent in the sunlight. Unable to control himself, Andersson seized the spade from the older of the men and flailed at the loose soil, shovelling sand and grit on to the casket as if determined to shield the dead girl from any sight of the world that had failed her.