There was a certain demonic quality about the voice chattering away on the other end of the line. 'What's OJ's favourite song? 'Mack the Knife'] What does OJ stand for? Open Jugular] What's OJ's favourite rock star? Mick Jagged]' And so it rattled on, a litany of savage tastelessness costing a mere 99 cents a minute.

Compassion has never been one of Los Angeles' strong points. Every day the city's highly paid television reporters reel off a list of fatal shootings and freeway accidents (known, cheerfully, as 'fender-benders' or 'bumper-thumpers') without so much as a shadow of concern flitting across their glossy, sculptured features. But the OJ Simpson affair has plumbed new depths.

More than seven weeks have elapsed since a passer-by stumbled across the bodies of Nicole Simpson, the one-time football star's former wife, and her young friend Ronald Goldman, sprawled on the pavement outside her townhouse in Brentwood, one of LA's more exclusive neighbourhoods.

Even by the standards of this crime-weary city it was a particularly brutal killing, described by one seasoned police detective as the bloodiest crime scene he had ever witnessed. The victim's throats had been hacked open, apparently with a knife. Goldman had been stabbed 17 times. Nicole Simpson, curled up in the foetal position, had a five-inch wound across her neck deep enough to have penetrated a vertebra.

Yet ever since this horrifying discovery, and OJ's extraordinary slow-motion freeway odyssey five days later, LA has been gobbling up the details with a relish bordering on naked glee. The same callous OJ jokes on the so-called 'Sick Joke' telephone line (set up by a comedy writer in need of cash) are swapped each night in the bistros of Westwood and Beverly Hills and hum around the city's e-mail systems the following morning.

It is fashionable to have the latest quip to hand. 'What's OJ's new name?' I was asked, quite suddenly, by a middle-aged woman at an orchestral concert in the Hollywood Bowl. She leant across from her box seat, eyes glittering mischievously as she waited to reveal her rib-cracking punch-line. 'Orange Juice - with a slice]'

The absence of any sense of gravity, let alone tragedy, over the case owes much to the peculiar nature of the city in which it occurred. Like anybody else, Angelenos are fascinated by a celebrity murder mystery (and they've had their share over the years: Marilyn Monroe, Fatty Arbuckle and Charles Manson). But in a city of 14 million people, comprised mainly of satellite communities tenuously connected by a network of freeways, such horrors seem unusually remote. Furthermore, each day the OJ story is beamed through the distortive prism of television, whose shallow and sensationalised reporting converts the real-life nightmare of murder into soap opera.

To be fair, it is a soap with a particularly compelling cast of characters: OJ Simpson, 47, the multimillionaire running-back turned corporate pitchman and NBC sports commentator, the all-American hero who is now prisoner 4013970 in an LA jail; Nicole, who lived in terror of her former husband's bullying visits and adored her two young children, but who, at 35, liked nothing better than to hang out at the gym surrounded by a gaggle of admiring young men, or to go for a spin in her white Ferrari. And Ron, the fresh-faced boy from the Midwest who represents an LA archetype - a muscle-bound, body-conscious waiter and wannabe model whose loves were surfing and roller-blading. With this trio, how could the world fail to be mesmerised?

But that doesn't quite explain the unbridled excitement, the absence of almost any trace of sensitivity. So what does? For one thing, the OJ Simpson affair has made Los Angeles feel important. The metropolis has long had an inferiority complex, especially concerning the East Coast. Many of its residents ignore West Coast time, leaping out of bed at 4am for fear that a rival in New York or Washington will steal a march on them. Now, for once, OJ Simpson has placed them centre-stage, confirming their long-held claim to be a city of comparable importance. This point was clear in the first television news reports: 'The attention of the world is on southern California tonight.'

Then there's money. Like any celebrity story in the United States, the OJ affair has attracted the usual shoal of minnow entrepreneurs with their trashy array of T-shirts, car stickers, key-rings, badges, mugs and even dolls. Scores of bigger fish are also cashing in merrily - so-called television 'experts', journalists, advertising executives, lawyers, private investigators and writers. It took 13 days for the first OJ paperback to hit the bookstalls. Two more 'quickies' have subsequently been churned out. 'Scandal seems to be our liveliest growth industry,' commented this week's People magazine, only half in jest. 'If exportable, it would cut America's balance of payments deficit to the bone.'

By far the most alarming aspect of this bonanza is its potential impact on Simpson's trial, scheduled to begin on 19 September. Although he has denied charges of first-degree murder, saying he is 'absolutely 100 per cent not guilty', none of the feverish activity that surrounds the case pays much heed to the need to protect either his or the prosecution's chances of a fair hearing. The Simpson-generated economic boomlet has even embraced direct participants in the case.

The LA District Attorney's office, which is leading the prosecution, has already abandoned an alleged eyewitness, a Santa Monica housewife who claims to have seen OJ erratically driving his white Ford Bronco near his ex-wife's house on the night of the murders. Her testimony was hurriedly set aside as unreliable after prosecutors discovered she had sold her story to the sleazy television show Hard Copy for dollars 5,000 (pounds 3,300) and pocketed a further dollars 2,600 from the supermarket tabloid the Star.

Prosecutors decided to persevere with another potentially important witness even though he, too, gave in to temptation after wads of cash were brandished under his nose. Jose Camacho, a shop assistant in downtown LA, was paid dollars 12,500 by the National Enquirer after he claimed to have sold a 15in stiletto knife to Simpson five weeks before the slayings.

Intriguingly, he remembered that OJ demanded that the blade be sharpened. Camacho gave evidence at last month's six-day preliminary hearing, in which a judge ruled there was enough evidence to send Simpson to trial. If Camacho is called to the dock again, it remains to be seen if jurors will consider his testimony worth listening to, or whether they will conclude that he has enhanced his memory to please his tabloid paymasters.

The buying up of witnesses has prompted the Speaker of the California State Assembly, Willie Brown, to draft a Bill banning them from selling their testimony But even if such a law is passed, it is unlikely to address the potential influence that large fees can have on professional experts, who are often paid handsomely for testifying.

OJ's 'dream team' of top lawyers, including Alan Dershowitz, who inspired Reversal of Fortune, the 1990 film dealing with the Claus von Bulow case, has been busy recruiting specialists to challenge the prosecution's DNA tests, should they reveal that the traces of blood found leading to OJ's front door, in his car, on a pair of gloves and at the crime scene, belong to him.

And what about the jurors? What's to stop them trying to find their way on to the panel that will eventually try Simpson simply so that they can sell the story afterwards? When the four Los Angeles police officers accused of beating Rodney King were tried in a federal court last year (having been acquitted on almost every charge by a state court in 1992), there was evidence that several members of the jury pool were keen to be selected merely because they wanted their lucrative 15 minutes of fame.

In fact, California juries commonly show symptoms of being star-struck. Some years ago a group of prospective jurors burst into delighted cheers when told they might hear a drink-driving case involving the former television chat-show host Johnny Carson. When the case was later dropped they groaned with equal volume.

Disturbingly, most of the frenzy surrounding the OJ scandal has been orchestrated by the people responsible for trying the case. Defence and prosecution attorneys have secretly fed the media with almost daily titbits in the hope of winning the battle for public opinion, and, more specifically, the hearts and minds of potential jurors.

Nor are they afraid to fight dirty. The worst example came a few days ago when a defence source leaked evidence to the New Yorker magazine suggesting that a detective, allegedly spurred by racist motives, tried to frame the superstar by planting a bloody glove in the grounds of his mansion.

The manoeuvre was intended to introduce a racial dimension into a case that has so far been broadly apolitical, although plenty of spokespersons are beginning to make their voices heard on issues ranging from spouse abuse and women's rights to police brutality. The detective has responded to the allegations by threatening to sue for libel.

But by far the most dramatic recent pre-trial revelation came not from lawyers, but from Lance Ito, the judge handling the case. Last weekend he decided to release all 460 pages of testimony given to an aborted grand jury hearing following Simpson's arrest, after sections had been strategically leaked. These included some of the juiciest morsels to date, namely, the story of Keith Zlomsowitch, a restaurateur who dated Nicole Simpson briefly in 1992 after meeting her in Aspen, Colorado, the winter resort of Hollywood's wealthy.

Mr Zlomsowitch described how OJ Simpson stalked and threatened his former wife, standing outside her apartment at night and glaring at her in restaurants. On one occasion the former footballer allegedly watched the couple through a window as they had sex. 'I watched you last night I saw everything you did,' he told them later.

Unsurprisingly, the news dominated the local headlines. Here was further apparent evidence that Simpson's generous smile, which beamed from so many Hertz advertisements, concealed a brooding, jealous temperament - the animus, perhaps, that might drive an otherwise decent man to commit two terrible murders.

As the city's millionaire anchormen and women related the testimony with hearty energy, LA was agog. It's a safe bet to say that few paused to wonder whether it was true. And it's an even safer bet that the Zlomsowitch story will soon form the kernel of another tawdry OJ joke - in a city where gags come cheap, but life sometimes seems to have no value at all.

(Photograph omitted)