FOR the people of Gwoza, the first sign that the assault on their town was unlike any other came three days after it fell, when corpses began to appear in the streets.

As the men hid, their women brought news that Boko Haram fighters, some clad in combat ­fatigues, were going door to door, searching for males of fighting age.

From his hiding place in his house Abbas Aga, 56, heard a knock on the door and voices asking his wife whether there were men inside. His wife said they had all left, but the fighters came in anyway.

Read Next

They found Mr Aga and five others, including a 15-year-old boy, dragged them outside and forced them to lie down on their stomachs in the dust.

The militants then ordered Mr Aga and another older man to stand. A fighter wearing a black turban told the two men to watch as he lifted his rifle and shot the boy and each of the younger men in the back of their heads as they lay faces pressed to the ground.

Scores more were killed in similar fashion on the orders of the town’s new ruler, a 50-year-old former bricklayer born in Gwoza. Residents left the corpses to rot in the sun for days, too scared to bury their dead.

Mr Aga and other residents of Gwoza were speaking at the former British military outpost of Maiduguri after fleeing the hilltop town of half a million people that the Islamists have renamed “The Gateway of the Faithful”.

Boko Haram grabbed the world’s attention when it kidnapped 276 girls from a school in nearby Chibok seven months ago, but it now seems determined to create its own “caliphate” across northeastern Nigeria, with Gwoza as its capital.

Mr Aga said his 25-year-old son, a member of a vigilante group formed to defend the town, killed two fighters on the first day with a home-made rifle. His son was later captured and killed by militants, who speared him through the mouth with a knife.

When the fighters stormed into Gwoza in August, no one thought they would stay for more than a night or two. But rather than leave, Boko Haram set about imposing its own form of brutal Islamic rule.

After the initial wave of killings, the fighters began to organise themselves into different units, each group identifiable by the colour of its turbans.

Those with yellow turbans formed the vice and virtue police, patrolling the streets and enforcing the group’s strict interpretation of sharia.

White turbans were worn by men responsible for preaching, and green by those charged with indoctrinating young men and persuading them to join the cause.

The most feared were the men clad in black and red turbans: those who killed with guns and those who slaughtered with knives.

Mustapha Bana, 41, a tailor, recalled how fighters in red turbans herded the men in his neighbourhood into a dusty square one day. They split the young and healthy from the old and infirm.

“They pick the strong and healthy to join them,” said Mr Bana, who escaped from Gwoza two weeks ago. He saw 10 young men carted off in the back of utes. Only two returned.

“The others refused to join them, so Boko Haram tied their hands behind their backs and put black blindfolds over their eyes. Then they rolled them on to their sides and slaughtered them like animals.”

The men in red turbans tossed the headless bodies into a trench that the Nigerian military had dug around Gwoza to prevent the militants from entering the town.

“That ditch has become a grave for our people,” lamented Suleiman Ali, 54, a teacher who escaped over the mountains a few weeks after the town fell to the Islamists.