In life, they envied her. In death, they trashed her

It was the pedicure that did it. Five years ago this Friday, Carolyn Bessette was due to meet her sister Lauren and husband, John F Kennedy Jr, at the airport for their flight to Hyannis Port, but she was late. This meant they would be taking off after dark, causing problems for John, an inexperienced pilot. When it later emerged that Carolyn had delayed the fatal flight because she was getting her toenails painted an exact shade of lavender, her reputation as an obsessive and difficult woman was sealed.

It was the pedicure that did it. Five years ago this Friday, Carolyn Bessette was due to meet her sister Lauren and husband, John F Kennedy Jr, at the airport for their flight to Hyannis Port, but she was late. This meant they would be taking off after dark, causing problems for John, an inexperienced pilot. When it later emerged that Carolyn had delayed the fatal flight because she was getting her toenails painted an exact shade of lavender, her reputation as an obsessive and difficult woman was sealed.

The pedicure story was just the first in a seemingly endless series of ugly revelations to have emerged since she died with her husband and sister when their plane crashed into the sea that July night. Instead of being canonised in death like other notable young beauties, Carolyn was demonised, her faults exposed and magnified in an act of public vengeance that has surprised even the most cynical New Yorkers. In a country in love with beauty and fame, why did this woman attract so much spite?

New York's obsession with Carolyn Bessette began almost as soon as she dared, in 1996, to marry America's prince. John, the handsome son of the murdered president and Jackie O, had already charmed New York as he tried to make his name with a glossy magazine, George. Carolyn seemed his perfect princess - dazzlingly beautiful, blonde, witty and clever, immersed in the fashion world and sublimely stylish. Every designer wanted to dress her; every woman in New York wanted to look like her. They were New York's first couple, yet from the start, as they were photographed bawling at each other in the street, something was amiss and already Carolyn was getting the blame.

First, the fashion publicist that John had met while shopping for suits insisted on holding the wedding of the year in 1996 on a remote island off the coast of Georgia, where no press, and hardly any of John's friends, could attend. Her desire for privacy would continue to thwart America's appetite for news of the couple. Instead of stepping out with a fixed smile, she became angry and obsessive.

Her husband had been raised to deal with the attention, and was adored for going about his business like a normal guy. He rode the subway, did charity work, played football with friends, and liked to hang out with his cousin by marriage, Arnold Schwarzenegger. Yet on their return from honeymoon, John asked the press to leave his wife alone. Rumours began to circulate that there were already problems in their marriage, and the tabloid-reading public soon developed an insatiable appetite.

John wanted children and America demanded a new generation of Kennedys, but Carolyn held off, telling friends she couldn't stand the thought of pushing a pram down the street followed by a pack of photographers. She fell out with his sister Caroline and was said to banish any of his friends she took against. The couple fought frequently; when John damaged a nerve in his hand, his friends weren't convinced that it really was a football injury. From time to time, he would move into the Stanhope Hotel on Fifth Avenue.

Before long, the most sought-after tabloid image of Bessette was a photo of her in tears. "She was married to the guy everyone in the world wanted," says Paula Froelich, a New York gossip columnist. "She made women jealous. No one understood how horrible life was under that degree of scrutiny. It was like Princess Di, only Diana at least knew how to pose."

Carolyn was frightened by the manner of Diana's death, say friends. But while Diana was forgiven her neuroses and manipulative behaviour after death, the vilification of Carolyn intensified.

The first assault came a mere four months after the air crash, when an unnamed friend of John's felt compelled to reveal how unhappy she had made her husband. This year, Carolyn's former boyfriend, Michael Bergin, published a book, The Other Man, about her sexual obsession with him which, he claimed, continued after her marriage. But the most vicious attack came in a book by self-styled insider Edward Klein, The Kennedy Curse. The book gave an account of a deeply troubled relationship between the headstrong American prince and his neurotic, self-obsessed, druggie wife. Klein quoted "friends" who attested to violent fights, psychosis and outrageously demanding behaviour.

The revelations were horribly intimate. Carolyn wouldn't sleep with John. She was a coke fiend. Klein describes John coming back to the apartment and finding Carolyn "sprawled on the floor, dishevelled and hollow-eyed, snorting cocaine with a gaggle of gay fashionistas". She was drawn as wild and unpredictable, with a filthy mouth.

America lapped it up, yet in a way, Klein's book proved a turning point. Klein made much of his relationship with Jackie Kennedy, and readers started to suspect a cover-up at work: that Carolyn was being blamed by the Kennedy PR machine for the death of its prince, when it was actually John's irresponsibility that was to blame. A year after the crash, the official report attributed it to John's lack of experience in flying alone at night. Klein's book further revealed that John had bought a plane too advanced for his experience and was not physically fit. After the report was published, Carolyn and Lauren Bessette's parents sued the Kennedy family for wrongful death and were awarded $15m.

A sympathetic new book by John Kennedy's old friend Robert T Littell, The Men We Became, published in June, softens the image of Carolyn further. Littell describes her as a deeply caring and empathetic woman with too much time on her hands, "unhappy and frustrated, like a caged animal backed against a wall". He insists Carolyn behaved out of a "fierce and uncompromising attitude toward her husband's fame".

The book helped to spread the feeling that there is something tragic and horrible about this woman being continually and cruelly exhumed. Her parents, who have lost two daughters in the most appalling circumstances, remain dignified. They have been forced to see their beautiful girl vilified by people who barely knew her, yet have never spoken out. Almost the only words we have from Carolyn's mother are from the night before the wedding, when she said she was worried for her daughter, unsure if this union was in her best interest. That sentiment, at least, has proved well founded.