Taking hostages is sanctioned in Islamic law. Here is a salient passage on this issue from a Shafi’i manual of Islamic law:
When an adult male is taken captive, the caliph considers the interests … (of Islam and the Muslims) and decides between the prisoner’s death, slavery, release without paying anything, or ransoming himself in exchange for money or for a Muslim captive held by the enemy. (Reliance of the Traveller o9.14)
A revered Islamic jurist, Al-Mawardi, agrees with Reliance of the Traveller:
As for the captives, the amir has the choice of taking the most beneficial action of four possibilities: the first, to put them to death by cutting their necks; the second, to enslave them and apply the laws of slavery regarding their sale or manumission; the third, to ransom them in exchange for goods or prisoners; and fourth, to show favor to them and pardon them. (Al-Ahkam As-Sultaniyyah (The Laws of Islamic Governance), 4.5)
“Italian priest kidnapped in Nigeria,” ANSA, October 13, 2017 (thanks to Insubria):
(ANSA) – Rome, October 13 – An Italian priest from the Rome diocese was kidnapped yesterday in Nigeria, sources said Friday, adding that the foreign ministry’s crisis unit has already been alerted and the Rome prosecutor’s office anti-terror unit has opened a probe.
The foreign ministry said no effort was being spared in the case, in a “dutiful” framework of confidentiality.
Rome prosecutors are investigating a suspected terror crime, with Islamist terrorists Boko Haram suspected. Sources said the priest, Florence-born Father Maurizio Pallù, who will be 63 next Wednesday, was stopped with four other people on his way to Benin City in southern Nigeria yesterday. They were stopped by an armed group that stole all their belongings and abducted the priest who has been on a mission to Nigeria for three years.
Pallù graduated in history before setting off as a lay missionary around the world, for 11 years.
In 1988, when his father died, he joined a Rome seminary and in 1991 was ordained as a priest. Two years later, spent working as a chaplain, he was sent to the Netherlands….