Since Omar Mateen massacred 49 people in an Orlando nightclub, the New York-born son of Afghans has been described as a homophobe who used a gay hook-up app, a jihadi who failed to understand that Isis and Hizbullah were enemies, and a jovial wife-beater who was both relaxed about his religion and furiously devout.
Mateen is not the first paradoxical jihadi. Amedy Coulibaly, who murdered customers at a Jewish bakery in Paris last year, died in the name of strict Islam but left behind a laptop full of child pornography.
Samy Amimour was known as a personable bus driver with secular parents before he set off for Syria and returned to unleash mayhem on the Bataclan club in the French capital in November. Among other recent terrorists are immigrants and natives, cradle Muslims and converts, hardened criminals and aspiring dentists.
Fifteen years after the September 11th attacks on the US there is still no consensus about what makes a terrorist. Mateen is widely considered a terrorist.
– who said he shot five police officers in
last week because they were white – is not, on account of apparently having no agenda beyond his own actions. And both men resemble in some aspects the mass shooters who have struck American schools, churches and other public venues.
Studies have suggested a history of depression or domestic violence might be a key indicator, or that a society’s attitude to the Islamic veil affects how likely it is to be struck. But psychiatrists, sociologists and other experts warn that such analysis often says less about the terrorist than the neuroses of a country seeking an explanation.
That has meant gun control in the US, secularity in France and multiculturalism in the UK. More troublingly, these experts say, the misguided belief that terrorists – today's jihadis, like nationalists, white supremacists and communists before them – have a single "profile" is distorting the West's response.
"Mateen may have felt like a husband in some situations, a security guard in another, a gay guy in another, an Isis member in others," says Marc Sageman, a psychiatrist and former CIA officer in Afghanistan. "People don't have a single social identity that transcends everything else."
Mr Sageman has worked as an expert witness on the defence team in terrorism cases. He has interviewed 30 violent terrorists and is dismissive of “armchair theorists” who do not enjoy such first-hand access. In 2008 he fought a public feud with other terrorism experts over his prediction “leaderless jihad” would eclipse al-Qaeda.
When attacks happen, Mr Sageman says, "two billion amateur Freuds" rush to extrapolate meaning from scraps of biographical detail. Seeking a pattern is futile, he says, beyond the fact Islamic terrorists consider themselves members of an ummah, a community of Muslims.
“It’s an imagined community; it lives on the internet,” he says. “You can be a punk, you can drink, you can be homosexual – it’s your own identification.” Those who identify with that community perceive it to be under attack from western military campaigns in the Middle East and react to protect it, Mr Sageman says, just as Americans rushed to join the armed forces after 9/11.
A Facebook post Mateen wrote during his attack appears to bear this out. "You kill innocent women and children by doing us air strikes," he wrote, according to Ron Johnson, chairman of the US Senate's homeland security committee. "Now taste the Islamic State vengeance."
But Isis, as Islamic State is also known, does not appear to have had any contact with Mateen, beyond its propaganda exhorting sympathisers to carry out attacks on their own. And in Europe and the US, terrorism experts say attempts to predict who is likely to answer that call risk backfiring.
"The problem is lots of people might fit a profile but not act, while those who do act, don't fit a pattern," says Martha Crenshaw, professor at Stanford University. A pioneer of terrorism studies, as far back as 1981 she argued the "limited data we have on individual terrorists . . . suggest that the outstanding characteristic is normality".
In a newspaper column after Orlando, Prof Crenshaw upbraided Donald Trump, the presumptive Republican presidential nominee, for his claim "thousands upon thousands of people" were coming to the US, "many of whom have the same thought process" as Mateen. When it comes to terrorist motivation, Prof Crenshaw wrote, "the possibilities are endless, from personal grievance to mental illness to social frustration".
In contrast with the "lone wolves" in the US, the authors of the Paris and Brussels attacks belonged to organised jihadi networks. Yet they also fail to conform to a pattern.
, a sociologist at the School for Advanced Studies in Social Sciences in Paris, has spent two decades analysing Islam in France. There, as elsewhere, the political responses have been based on an erroneous faith in profiling, he says.
“[Political leaders] are playing this game. They need to tell the citizens that there is a type of person we are going to fight against. But we can see at least five or six types of person who will kill.”
In the UK, Paul Rogers, author of a forthcoming book on Isis, argues the search for a unique terrorist profile is "a diversion". "It's looking for easy answers without facing up to much bigger problems."
Copyright The Financial Times Limited 2016