Saint Cassie of Columbine High

If you don't yet know who Cassie Bernall is, you soon will. Cassie is America's newest icon, and her radiant face and gleaming blonde hair will shortly be gracing the windows of every bookshop in the United States, and a good few in Britain as well. She looks the very picture of vibrant American youth - except that, like every true icon, Cassie Bernall is dead.

You remember the shootings at Columbine High School in Colorado in April, those terrified children running from the building with their hands over their head? Cassie was one who did not come out. Aged 17, she was shot at point-blank range in the school library, and the circumstances of her death, as retold by fellow pupils who survived, support the conclusion that she was not so much killed as martyred.

Cassie's hagiography opens on that April day, when the killer pointed his gun at her and asked a life-or-death question: "Do you believe in God?" Cassie, it is related, looked back and replied: "Yes, I believe in God." It was the last thing she would ever say. The gunman pressed her: "Why?" Before she could answer, he pulled the trigger.

As the tale gets told time and again, details are added and embroidered. Cassie is said by some to have been reading the Bible when the gunmen entered. She spoke "strongly enough to be heard by classmates cowering under nearby tables". Some versions have her pausing almost interminably before giving the fateful answer; others have her answering with the single word "Yes". Some have the gun held to her head; others have her clasping her hands and closing her eyes in prayer. Some interpret the schoolboy killer's "why?" as mocking rather than enquiring; others say that he added: "There is no God."

Cassie's close Christian family enters the picture. It is her grandmother who is credited with first calling her a martyr. Dave McPherson, a minister at Cassie's church, said he was with the family while they waited in vain for Cassie to return home: "When we first heard... about Cassie's last words," he related, "her grandmother said, `My God, my granddaughter was a martyr'."

Her death is made more poignant - and her "martyrdom" more manifest - by her troubled teenage years. While there were other professed Christians among the dead at Littleton, none had a record of innocence, sin and redemption to approach Cassie's. In an interview shortly after their daughter's death, her parents, Misty and Brad Bernall, told ABC News that when Cassie, a smiling and sociable child, entered her teens, she had started down a road very similar to that of her eventual killers. "I had that gut feeling," Misty Bernall said, "that something was wrong... I didn't feel like either of us [herself or her husband] had any connection with her."

They found letters in her daughter's room that, her husband said, "were talking about things they could do to parents that could be just tragic". As well as plotting violence, it emerged that Cassie was experimenting with alcohol and drugs, dabbling in witchcraft, and periodically considering suicide.

When her parents, both Evangelical Christians, finally imposed their own discipline and transferred her to a new school - ironically, Columbine High - they also referred her to the local minister, Dave McPherson. He recalls meeting a sullen girl who spoke in monosyllables, and thinking: "There is no hope for that girl... Not our kind of hope." But as Rev McPherson tells it, Cassie returned from a weekend church retreat transformed, bounding up to him after a Sunday morning service to say of her conversion: "You'll never believe what happened..." In her father's words: "When she left, she was this gloomy, head-down say-nothing [girl]. When she came back, her eyes were open and bright ... It was like she was in a dark room and somebody turned the light on."

She took to wearing a "What Would Jesus Do?" bracelet to remind her of her new-found commitment, and she took up voluntary work, lunching with prostitutes and drug addicts at an inner-city church centre. According to friends and relatives, she planned other good works, including having her luxuriant hair cut in order to provide wigs for child cancer patients.

This saintly biography continues, but is usually rounded off with words of her own which suggest that Cassie's life mission was nearing completion. "Mom, it would be OK if I died," Misty Bernall quoted her daughter as saying in the last months of her life: "I'd be in a better place, and you know where I'd be." After her death, her brother found on her desk a poem that has been hailed as showing the gift of prophecy. It reads in part: "... to find out/ what it means to suffer and to/ die with him/ So, whatever it takes, I will be one who lives in the fresh newness of life of those who are alive from the dead."

As Cassie's story has been told and retold, it has allowed Americans - predominantly, it should be said, younger, white Americans - to believe that some good has come out of an incomprehensible evil. Shocked that the shooting rampage was possible in a pleasant suburb that looked like theirs, many have found hope in the idea that Cassie lives on through her example. "We don't pretend to fully understand," said Cassie's parents, "why the tragedy at Columbine happened... yet we know that God is working good out of this horrible nightmare."

For teenagers affected by the slaughter that cost 15 lives and left another two dozen injured, Cassie Bernall is the alternative face of Littleton, a face that covers the malign images of gun-toters in trench-coats and allows them to fade from view. The directness and simplicity of her answer, along with its fateful consequences, spoke to them as little else in recent years. A Time magazine columnist caught some of her appeal when she wrote: "We expect our martyrs to be etched in stained glass, not carrying a backpack and worrying about their weight and their finals."

The word "saint" is still rarely spoken, but the word "martyr" is on many lips. At Cassie's funeral, her friends and contemporaries wore navy- blue T-shirts with the one word "Yes" printed across the front, and a dictionary definition of martyrdom on the back. Next month, a book written by Cassie's mother comes out; it's called She said `Yes': The unlikely martyrdom of Cassie Bernall.

And despite Mrs Bernall's contention that her daughter was "no saint", the hagiography is fast outpacing her efforts to paint a balanced portrait. Memorial sites, many of them run by teenagers, proliferate on the Internet. One, headed "In Memory of Cassie Rene Bernall, 1982-April 20, 1999" shows a portrait of Cassie, in virginal pastels, with a youthful Christ looking down. Alongside the portrait, a small dove flaps its wings into eternity. The text beneath recounts her martyrdom.

Over the summer, Cassie's example has been cited time and again at youth camps and prayer meetings, and staff and volunteers at the Bernall's home church, West Bowles Community Church in Littleton, have found their time increasingly taken up with requests from all over the US for information and speakers. Cassie's fellow pupils have so far fulfilled more than 30 speaking engagements. "Everywhere you go, [young people] say how it's affected them," explains Shauna Gauthier, a youth leader at the church. "Many say that it's the biggest thing to have happened in their lives."

In the US - a country where more than 60 per cent of the population regularly attend church - only a very few have questioned the health of what is rapidly becoming the cult of Cassie Bernall. You have to go all the way to the American Atheists organisation before you encounter any openly adverse reaction. They accuse Christian groups of exploiting Cassie's story to proselytise more aggressively. Arguing that she was doomed however she answered, they ask: "Did Cassie really die for her faith?" But they admit that it may be too late to change public opinion.

For the moment, some people are still writing the word martyrdom as applied to Cassie Bernall in quotation marks. But for how much longer?

"She said `Yes'..." (Plough, pounds 7.99) is out on 10 Sept