Many observers - too many - were quick to assume that the atrocities in Norway were committed by Islamists.
The plague of Islamophobia rears its head in Norway
In its surprisingly slim coverage of the atrocities in Norway, the conservative French daily newspaper Le Figaro reported that thoughts on the identity of the culprits "turned logically" towards Islamist terrorists. But long before copies reached newsstands it was known that the perpetrator of the attacks on government offices in Oslo and a youth camp outside the capital had nothing to do with Islamist terrorism.
Indeed, the profile that emerged of Anders Behring Breivik, 32, presented an individual who could hardly be more different. He was described as a devout Christian and anti-Muslim. He had connections to the Norwegian far right, belonged to a Swedish neo-Nazi internet forum and championed the anti-Islam PVV movement of Geert Wilders in the Netherlands as "the only true party for conservatives".
Much of this became known within hours, as the death-count spiralled alarmingly towards a figure close to 100. Cyberspace was dotted with clues to his obsessions.
Le Figaro, up against deadline, was certainly not alone in giving early prominence to the theory of Islamist guilt. "I hope Sky News and Fox News are proud of themselves for jumping to conclusions," a friend in London tweeted later. "It's not always Al Qaeda."
In other words, the booming culture of Islamophobia that has spread through Europe virtually ensures that each time a bomb goes off in a western city, fingers of suspicion are directed first of all towards Muslims.
I have reported a good deal on the extreme right as it has gone about securing its increasingly loud voice: the British National Party in the UK, the Front National in France and Mr Wilders in the Netherlands. And the theme central to their supporters' thinking is "Islamification". The word comes readily to the lips of those who resent any community gesture that recognises Muslim sensitivities, any move designed to make Muslims feel as valued by society as anyone else.
And from that resentment, fear and suspicion quickly breed. Even among people who would be indignant at being thought racist, it is common to find confusion between a religion and the actions of a few of its faithful.
At a website that I run (www.francesalut.com), discussing concerns that France may be in for a dirty presidential election , a visitor described Islamophobia as a "particularly nauseating prejudice".
Which drew this response from another reader: "Islamophobia is not a prejudice. It is a fear, just like arachnophobia, and no one practises it. People suffer from it."
She went on: "There was little or no Islamophobia 30-odd years ago when terrorists hijacked planes or when Palestinian terrorists killed Israeli athletes at the Munich Olympics. Since the arrival on the scene of (Osama) bin Laden, prompted by the basing of American troops in Saudi Arabia while freeing Kuwait from the Iraqi invaders, and the threats issued by him and his cohorts, Islamophobia has leaped into life. I expect 9/11 encouraged its growth."
And she concluded with this: "Yes, I am Islamophobic. I fear for my children who live and work in London. I fear another 7/7 attack. I am not self-righteous, certainly not as self-righteous as those of the loony, liberal left perched loftily on their moral high ground."
The words, long-winded as they were, merit repetition because they seem to encapsulate what disturbingly large numbers of people, while doubtless seeing themselves as tolerant and fair, have come to believe.
Reflecting on the hideous events in Norway, I found myself lingering over a notice in the parish church near my home in France: "Don't just call yourself a Christian," it reads. "Act as one."
It would surely defy any rational imagination to come up with a model of Christianity that was fairly represented by someone bombing the prime minister's office in an Oslo square before massacring scores of innocent young people at a summer camp run by the ruling Labour Party on Utoeya island.
Few in the West will come to think of the Norwegian bloodshed as establishing a direct, modern-day link between Christianity and mass murder even if the killer appears to have been driven to his wicked actions in part by an unhealthy attachment to Christianity.
But if that is so, why should it seem so natural to detect some unbreakable connection between Islam and evil deeds committed by followers of that faith, who may also purport to be serving its interests?
According to www.adherents.com, an unaffiliated and widely quoted American database of religious statistics, the number of Christians globally is estimated at 2.1 billion (33 per cent of the world population) and Muslims at 1.5 billion, or 21 per cent.
It is fair to assume, even allowing for deeply held grievances and strong political views, that no more than a tiny minority of either figure wish to do more than live peacefully, free from oppression and free to worship in accordance with their faith. In any calculation of how many Christians might feel Anders Behring Breivik's alleged crimes of unspeakable barbarity were committed on their behalf, that tiny minority would shrink to negligible levels.
And while the repercussions of conflict mean bin Laden undoubtedly had some followers, are they not in turn overwhelmingly outnumbered by Muslims disgusted by the slaughter of innocents in terrorist attacks?
A lawyer acting for the tall, blond Norwegian is quoted as saying his client admits responsibility, accepts his actions were "atrocious" but believes they were "necessary" and will explain himself in court.
Perhaps it is too much to hope that when people consider what he says, now or later, and also recall who was originally assumed to be the probable cause of the carnage, they will realise that while Islamophobia is indeed a fear, it is also - to quote my website correspondent - a "nauseating prejudice".
Colin Randall is the former executive editor of The National