According to El Pais, the families joined the ISIL pursuing their "jihadist dreams" but also for money. Apart from the initial payment they received free houses and monthly payments.
"There is a reward for those moving with wife and children. They pay up to 20,000 euro if the family has four members… it is much more than what they give as dowry to women traveling to get married there, which is 1,200-1,400 euro," Spanish National Court prosecutor and coordinator on issues of international terrorism Dolores Delgado told the newspaper.
The newspaper sources suggest that the ISIL needs foreign families, who are fully dependent on the terrorist group, to outbalance the rejection of the ISIL-imposed lifestyle by the peoples on the group-controlled territories.
The ISIL is a Sunni militant group in control of vast territories in Iraq and Syria. The militants are notorious for their brutality and human rights abuses.
According to US National Counterterrorism Center estimates at least 20,000 foreign fighters have joined the ISIL.
Previously it was believed that the group mainly targets its propaganda at single young people.