Was the display as deterence of a kidnapping group, killed in crossfire by the Taliban, Islamic?

The Guardian, a left leaning liberal paper based on the UK reported on the killing of a kidnapping group in Afghanistan. There were four of them and they had abducted a father and son. The kidnappers were killed during crossfire in a rescue mission. The father and son were rescued without injury, though one Taliban fighter and a civilian were injured. The bodies of the kidnappers were hung up on cranes in the main square in Herat with a warning written on paper pinned to their bodies: >Whoever kidnaps others, will end up like this. Mullah Nooriddin Turabi, one of the founders of the Taliban, said: >Everyone criticised us for the punishments in the stadiums, but we have never said anything about their punishments and their laws. No-one can tell us what our laws should be. We will follow Islam and base our laws on the Qu'ran. There are four laws schools (*madhab*) in Islam: Hanafi, Habali, Maliki & Shafi'i. Which one do the Taliban subscribe to and is the deterrence described above prescribed, sanctioned by that law school?