It is fast becoming the town that dare not speak its name.

A steady rain fell on Dewsbury yesterday morning, but it would take a biblical flood to wash away the stains that discolour this once-proud Yorkshire mill town.

The murder of a boy aged 17, beaten so savagely that his body was initially unidentifiable, at the weekend was merely the latest in a grim litany of incidents that carry a “made in Dewsbury” stamp.

A kidnapped schoolgirl, a suicide bomber, the attempted lynching of a boy aged 5, the teaching assistant who refused to remove her veil, a record BNP vote . . . from Shannon Matthews to Mohammad Sidique Khan, Dewsbury was home to them all.

Seven children, including four aged 15 and two aged 12 and 13, have been arrested on suspicion of murder since the violent death on Sunday of Amar Aslam. A quiet, shy boy who was something of a loner, he appears — by some accounts — to have been selected for punishment by a gang of idling youngsters seeking some sport.

They overcame the sun-soaked boredom of a lazy Bank Holiday weekend by kicking and beating the defenceless teenager until he was dead.

Police are investigating reports that the killing was videoed on a mobile phone and that the footage was later forwarded so that others could share the moment.

Amar’s body was found by two passers-by among the wild flowers of a walled garden in the grounds of Dewsbury’s biggest and most attractive park.

The 70 acres of Crow Nest Park, once the home of a wealthy textile merchant, were bought by the Dewsbury Corporation in the 1890s. Its official opening in 1893 attracted 40,000 people and to this day its ordered landscape — manicured lawns, wide paths and statues honouring the dead of past conflicts — speaks of grand Victorian ideals.

The town’s local newspaper, the Dewsbury Reporter, celebrated its 150th anniversary this year.

In 1858 its first editorial pledged “to promote the elevation and advancement of all classes by the dissemination of great principles, the inculcation of a liberal and generous spirit, and the enforcement of manly, independent and noble action”.

What price nobility today? To the outsider, Dewsbury appears fractured, a town divided between two communities — white and Asian — living in mutual incomprehension.

Thousands of Muslim immigrants, mostly from Pakistan and Gujarat, in India, arrived during the 1950s and 1960s to answer a shortage of low-cost labour in the wool mills.

For many, home is Savile Town, where terraced homes, businesses, schools and mosques occupy a loop of the River Calder to the south of the town centre. This is where Mohammad Sidique Khan, leader of the suicide bombers who attacked London in July 2005, lived in his final months. His wife, Hasina Patel, worked at the same Church of England junior school where Aishah Azmi gained notoriety in 2006 by refusing to remove her full-face veil in the classroom.

Ms Azmi’s father was the headmaster of the Islamic seminary attached to Dewsbury’s giant Markazi mosque, which has adopted an isolationist approach to life in a non-Muslim country. The Markazi is the European headquarters of the global Islamic missionary movement Tablighi Jamaat, which wants to build Europe’s biggest mosque alongside the Olympics site in London.

One of its leading British ideologues has argued that Muslims should feel the same hatred for the ways of Jews and Christians as they do “for urine and excreta”.

To the west is the mainly white Dewsbury Moor estate, which gained national infamy during the 24-day police search that was triggered when Shannon Matthews, 9, went missing on her way home from school. What dismayed and depressed onlookers was not so much a sink estate as the sink lives that were being led there, dominated by a poverty of expectation that is passed like a badge from generation to generation.

The far-right BNP has enjoyed some success in persuading whites that they should resent the perceived favouritism granted to neighbouring, non-white communities.

In 2005 Dewsbury produced the highest BNP vote — more than 5,000 — of any constituency in Britain.

So two worlds exist in the same small town, its total population less than 55,000, each at best a polite stranger to the other.

Margaret Watson, the president of Dewsbury Chamber of Trade, is a staunch defender of her town but suggests that whites and non-whites “like to live in their own communities”. “It’s human nature to favour your own neighbourhoods, your own people, your own culture. We don’t have the opportunity to come together,” she said.

The irony is that Crow Nest Park, halfway between Savile Town and Dewsbury Moor, was a place where one might have expected everyone to feel at home.

There is much talk of inter-ethnic rivalry, yet — perhaps because they encounter each other so rarely — incidents of race-linked violence are rare in Dewsbury.

In cases where the town has gained unwelcome headlines in recent years, the incident has tended to be confined within one community or the other.

And so it continues. The seven young people, aged from 12 to 20, who are being questioned about Amar’s death are all Asian.

The dead boy’s sister, Samreen Aslam, said yesterday that he was the baby of the family and had been very close to all of them, especially his mother. Amar’s nickname was “Moon” because “he was like a shining moon to us”, she explained, describing a boy who “was always thinking of others” and was always respectful of his elders.

“Nothing can replace our brother and we still believe he will come through the door. This has shattered our family.” she said.

The talk among locals yesterday was of rival groups, some white, some Asian, each protecting their own little turf — usually hanging around the corner shop and trying to look threatening to other teenagers — while talking big about guns and drugs.

One of the group, the West Town Warriors, is said to regard the park as its territory. Those arrested may have links to another gang, from nearby Ravensthorpe.

Amar, who was slim, had been ill and would sometimes cross the road because he was too embarrassed to be spoken to, may have been caught in the middle.

A family of ducklings were being given a swimming lesson by their mother yesterday as, underneath them, police divers scoured a lake in the park for a piece of wood that may have been the murder weapon.

Even in the drizzle, it seemed a place of serenity. A plaque on the wall explains that the garden was created “for birds, bees and butterflies”. And not murderers, it might have added.

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