In the neighbourhood where Mohamed Merah grew up, and was last seen joking with friends days after he had killed three French soldiers in a pair of shootings, the message to outsiders is clear: he was one of our own, no matter what he did.

The self-styled Islamist militant tore a wound in France's fragile sense of community when he gunned down the soldiers, sons of North African immigrant families like his own, and then a rabbi and three Jewish children - all in the name of al Qaeda.

For days, Toulouse lived in fear of the scooter killer.

France reeled at the worst such attacks since a bombing campaign involving another young son of Algerian parents from another rough provincial suburb, Khaled Kelkal from Lyon, killed eight people in 1995. President Nicolas Sarkozy put his re-election campaign on hold to call for unity. Tens of thousands of people marched silently in memory of the victims.

But in Les Izards, the 1960s housing project where Merah, 23, felt most at home, the reaction to his rampage has been one of anxious defiance of outsiders trying to peer into what seems like a closed world, cut off from elegant downtown Toulouse by its poverty, by crime and, locals say, by racial discrimination.

I'm going to tell you one thing: he was a kid from this neighbourhood and we support his family no matter what people say on TV, said one middle-aged mother of Algerian origin who said she had known Merah when he was a child in Les Izards.

Typical of others in the area of low-rise blocks and tidy squares a 15-minute metro ride north of the city centre, she did not want to be named when speaking up for the man who was, briefly, public enemy No. 1: He was one of ours, she said. And we will never be sure of what really happened.

SENSE OF ALIENATION

Dozens of conversations with neighbours reveal a portrait of Merah as a fragile, emotional young man who spoke constantly of his absent father and had withdrawn into a state of anxiety in his final weeks. They left question marks over his own claims to belong to an identifiable international movement, despite recent travels to the Middle East, Pakistan and Afghanistan.

They also show a powerful sense of alienation from the rest of French society in Les Izards, a community of 5,000, mostly families who arrived from France's North African former colonies a generation or two ago. Merah spent much of his youth living there with his mother, two brothers and two sisters.

Officially labelled a sensitive urban zone due to high rates of poverty, joblessness and criminality, Les Izards offers a window into the urban enclaves where French academics say exclusion is deepening and more grandchildren of North African immigrants are turning to Islam as a form of social protest.

The fear is, there may be more Mohamed Merahs in waiting among Europe's largest Muslim community, of some five million people in France - a worry that may partly explain Friday's roundup of 19 suspected militant Islamists as Sarkozy's government asserts a firm grip on security ahead of a series of presidential and parliamentary elections starting on April 22.

In Les Izards, there is evidence of earlier failures in policy, however, notably of Sarkozy's efforts to assuage the rage and resentment that fuelled an explosion of rioting across France in 2005 - and still simmers below the surface.

By one local account of a confrontation between youths and the authorities in the neighbourhood, after Merah was killed trying to escape a siege of his apartment, one young man was arrested after yelling at the police ranks: My friend Mohamed is a real man - too bad he wasn't able to finish the job!

Hatem Ben Ismail, who runs several community centres in the area and describes himself as the go-to guy on Les Izards, says he simply hesitates to discuss in public the mood among the youngsters he tries to help: The situation with the young people, he concluded, is just too explosive.

ELDER BROTHER

By the bakery where Les Izards residents said they last saw Merah hanging out, two days before his last attack, on a Jewish primary school on March 19, a group of surly young men in tracksuits and dark glasses glowered at oncoming cars.

When, on a reporting assignment this week, a Reuters photographer approached the youths, all in their late teens and early 20s, she was warned, with a stream of expletives, to leave - or have her car smashed up.

Merah's acts have brought unwanted scrutiny to a neighbourhood known to police as a hub for trade in cocaine and heroin, as global media lay siege and police seek to discover whether Merah had help in planning and carrying out his attacks.

Abdelkader Merah, 29, the gunman's older brother, has been charged with complicity in murder and theft and involvement in terrorism. An austere figure and a more overtly devout Muslim than his sibling, who rarely prayed at the mosque, officials suspect Abdelkader may have exerted a strong influence on Mohamed since their father returned to Algeria in 2006 or 2007.

He was difficult to approach, much more austere and distant than Merah - the sort who did not look women in the eye, said Patricia, a mother of Italian and Algerian background who had known Mohamed Merah since he was 14 and said she was close to his brother's wife.

Police also suspect that a third man may also have been involved. But in Les Izards, where a movement is under way to mount a demonstration in support of the imprisoned Abdelkader Merah, many simply find the idea of an organised plot by the Merahs and others absurd. Some mutter of official conspiracy.

A PLAYFUL BOY

Mohamed Merah was a playful teenager, zooming between Les Izards' apartment blocks on his motor scooter, no different from many others. A lover of cars and soccer, he went to nightclubs with friends and left school at 16 to work as a panel-beater. Though his travels heightened his interest in Islam, he prayed only infrequently and rarely went to mosque.

I don't condone what he did, but I can only talk about the Mohamed I knew, who was a kid like all those over there, said Patricia, who like many found it simply hard to compute the crimes to which police said Merah confessed before being killed.

When I last saw him he was with his friends by the tobacco shop, she said. He played with my boy and gave him two euros to buy candy at the bakery.

Few of the young men of the neighbourhood would open up to outsiders. Among those who did, some found conspiracy theories more convincing than that one of their own could be a killer who amassed an arsenal of guns and targeted his victims carefully:

All of this is a setup to get people to vote for Sarkozy, said Hamed, a boy in his late teens riding a bicycle through the village-like warren of apartment blocks.

Among people who knew Merah and who do accept the police version of events, including his lawyer, the most common explanation is not a calculated militant operation but a fit of rage brought on by a mix of trauma over horrible things seen during his travels and disappointment over his breakup with a girl to whom he was engaged in a religious ceremony in December.

Patricia said that Merah may have been upset about the breakup with his fiancée, a woman from a nearby neighbourhood, which coincided with his serving a month in jail in February for driving without a licence.

First arrested at 17, Merah had a number of run-ins with police as a teenager for stone-throwing and shoplifting, before being sentenced to 18 months in jail in 2007 for a robbery.

Lawyer Christian Etelin, who had represented Merah since he was 16, described the week-long series of gun attacks as entirely the product of an internal mental disturbance: It was an episode of paranoid schizophrenia during which he completely disconnected from reality, Etelin said. He was a fragile kid.

I don't believe he was an Islamist.

Merah's troubles may have built up recently, with some friends also saying that he had even tried to join the army and was depressed by rejection - adding a further speculative angle to attempts to understand his shooting at soldiers. In 2009, a clinical psychologist, Alain Penin, examined Merah after a suicide attempt in prison and found the then 20-year-old anxious and introverted but not psychologically disturbed.

At the root of problems, Penin told French media, Merah had dealt poorly with his parents' divorce when he was five years old and developed a withdrawn personality after his father, Benalel Merah, left France for Algeria in 2006 or 2007.

His departure after serving a prison sentence in France for cannabis trafficking had an impact on Mohamed, who often referred to his father in conversation and came to rely more on his older brother for emotional support in his absence.

US AGAINST THEM

As shock over Merah's killing spree gives way to soul-searching, concern for many in France is shifting to how the gritty, impoverished suburbs provide a breeding ground for angry and fragile youths like Merah to turn to radical Islam.

In 2008, Sarkozy's conservative government unveiled a billion-euro plan to revive the depressed urban areas and avoid a repeat of riots that lasted for months in 2005 after the deaths of two teenagers of immigrant origin near Paris.

The programme, which aimed to create 45,000 jobs and invest heavily in education, never got off the ground as public finances were squeezed by the global economic crisis.

Meanwhile, dismal job prospects have worsened feelings of exclusion among second- and third-generation immigrants, bolstering the appeal of radical Islam and discrediting the liberal values of a France many feel has rejected them.

They are translating social discontent into a religious vocabulary, Gilles Kepel, a professor at Paris's Sciences Po university, told the Arte television channel, warning that while many were content to adopt moderate Islamic ideas, a minority were drawn to more fundamentalist forms of their religion.

Toulouse city officials say an 'us against them' mentality deepened in the wake of the 2005 riots as rising unemployment has taken a disproportionate toll. Jobless rates for under-30s in sensitive urban zones like Les Izards can hit 30 percent - a level some in the area put down to racial discrimination.

Young people in this neighbourhood have degrees but when they go looking for work they are told: sorry sir, there's nothing we can offer you, said Belkouassa Bebel, head of Egalite, a group that lobbies for funding and activities in another poor Toulouse suburb, Empalot.

Finger-pointing at Islam by Sarkozy, whose five-year term has seen the full-face veil banned in France, and by his far-right rival Marine Le Pen, has not helped calm tensions, said Jean-Paul Makongo, who works for the Toulouse local authorities on promoting diversity. Instead, some of France's leaders have challenged the youth of Les Izards to confrontation.

The thought process is this: since you have discriminated against me, I'm going to do the same to you, Makongo said of the way the youngsters in the suburbs were reacting.

Several residents of Les Izards, in illustrating that sense of confrontation with the French state, alleged that on the day Merah was killed, police cars drove through the neighbourhood honking car horns in the manner of jubilant sports fans.

If we don't want to produce more Mohamed Merahs, Makongo warned, We are going to have to work a lot harder to reach these kids through dialogue - and find them jobs.

(Editing by Alastair Macdonald)