Timeline: How IS spotlight fell on West Yorkshire

Zaynab Iqbal and Mariya Iqbal at Heathrow Airport. They are now believed to be in Syria. Picture: Ross Parry Agency

The news that a Dewsbury teenager had blown himself up in Iraq, and that 12 members of a Bradford family had disappeared before travelling to war-torn Syria, sent shockwaves through the county and sparked a fierce national debate about the growing threat of radicalisation.

Six days after the news of the death of 17-year-old Talha Asmal emerged on Sunday, the nation is still searching for answers. How British citizens could be turned against their country by the poisonous doctrine of ‘Islamic State’, and perhaps more importantly, how the tide of young Muslims to Syria can be stemmed.

News that Asmal, described as “lovely and sweet-natured” by a former Dewsbury MP and friend of his family, and his fellow Dewsbury 17-year-old Hassan Munshi, had travelled to Turkey, broke in early April.

The two boys were last seen by their families on March 31 when they are believed to have flown from Manchester to Dalaman. Munshi - a former pupil of Dewsbury’s Westborough High School - and Asmal - a pupil at Mirfield Free Grammar’s sixth form - were thought to have crossed the border into Syria.

A statement released by the boy’s families on April 9 said they were “in a state of profound shock” and were extremely concerned about the safety of the “ordinary Yorkshire lads”.

Two months later, on June 14, it became clear that Asmal had become Britain’s youngest ever suicide bomber after apparently blowing himself up in Iraq.

Four suicide bombers attacked forces near an oil refinery south of Baiji, with social media reports linked to IS saying Asmal, going by the name of Abu Yusuf al-Britani, had taken part in the attack.

Members of the Dewsbury community reacted with shock and sadness to the news, condemning IS for “brainwashing” and “grooming” Asmal.

Within 24 hours, the ease with which Britons could slip out of the country intent on travelling to war-torn Syria, the Middle Eastern nation mired in a bloody civil war since 2011, became apparent.

More than 220,000 people have been killed in the conflict in Syria so far, while IS, the extremist group that grew out of al-Qaeda in Iraq, has taken control of huge swathes of territory.

On Monday, fears began to grow that 12 members of the Dawood family from Bradford may have joined the more than 700 British residents who had travelled there.

A statement issued by the family’s solicitors said they were “extremely concerned” about the whereabouts of sisters Khadija, Sugra and Zohra Dawood and their nine children, aged three to 15, after they travelled to Saudi Arabia on an Islamic pilgrimage.

As police and counter-terror officials scrambled to locate the missing 12, who are thought to have boarded a flight from Medina to Istanbul in Turkey, it emerged that the brother of the three sisters had travelled to Syria months earlier.

In a press conference later in the week, Akhtar Iqbal and Mohammed Shoaib, the husbands of two of the missing sisters, were overcome with emotion as they appealed to their missing relatives.

In a direct appeal Mr Iqbal said: “Please, please call me. It’s been eight, nine days, you are out and we don’t know where you are. I miss you, I love you. All of you, I love you a lot. I can’t live without you.”

Police would not reveal whether the family had been under surveillance, but did confirm they had tried and failed to leave thecountry earlier in the year after a security check meant they missed their flight to Saudi Arabia.

Officials later said that one of the family members had made contact with the UK, giving the strongest indication yet that they had crossed from Turkey into Syria.

And those fears seemed to be confirmed today when a people smuggler with links to IS told the BBC that the three sisters and their nine children had split into two groups to cross the border.

Kalsoom Bashir, director of counter-extremism organisation Inspire, said: “For many British Muslims, the past week has been as shocking as it has saddening. We have been buffeted by terrible news about young people drawn by Isis into a nightmare of violence in Syria and Iraq.

“But we cannot afford to stand on the sidelines, perplexed - because this is an outrage, which needs to be understood, and stopped.”