What could possibly persuade women from Germany, Indonesia or Russia to leave peaceful nations for a new life in a pariah 'state' at war with all around and with streets soaked in the blood of its victims?

For Difansa Rachmani, it seems, the answer is health care.

A mother-of-three at the time of her immigration to the so called Islamic State in the summer of 2015 - two months after 'the Caliphate' was declared - she told Sky News she made the journey because she'd been promised surgery.

She said she had also been promised help with her autistic three-year-old who could not walk.

Difansa chose, she said, to "put to one side" the atrocities she knew about from the internet.

On her arrival she was indeed treated for her condition. As was her son who was able to walk after the two of them travelled to Mosul to get the best medical attention the Caliphate could offer.

One of a family group of 17 - nine women, five men and three children - who moved en masse to a new life in Raqqa, she said that life for them turned sour when the men folk refused to do military service.

The males are currently under interrogation in Kobane by Kurdish intelligence officials while the rest of the family await their fate in a refugee camp in Ain Issa.

Sisters Nur Kharadhania, 19, and Syarafina Nailah, 21, insist the lure of the Caliphate came from online propaganda. Nur especially had an online relationship with a man and a woman already in Raqqa.

She was promised a "great salary" and told that she would be given a large house for her extended family.

Aged 17, she was groomed - almost certainly by a unit of ISIS specialists led by Sally Jones, a convert from Kent who is the widow of Junaid Hussain, the Eyad of the Caliphate's digital jihad.

CLICK TO READ MORE AT SKY NEWS.