In an article at Foreign Policy titled The Disappeared, James Traub reports on journalists who have been kidnapped in Syria, either by Islamist extremist rebels or by forces for the regime of President Bashar al-Assad. At one point he was introduced to (emphasis added):
… Hamza Ghadban, a Syrian journalist. … He was convinced, as many rebel sympathizers are, that the regime has subterranean connections with the foreign jihadists. He told me that the ISIS camp in Aleppo had been unscathed until the jihadists decamped, while the next-door headquarters of the Tawhid Brigade, affiliated with the FSA, had been leveled by government artillery. In Raqqa, too, the ISIS base had not been shelled. It’s also widely believed that in the summer of 2012, Assad released from prison some of the Sunni extremists who had fought American troops in Iraq, and who may then have joined with foreign fighters to form ISIS. Those fighters now seem at least as preoccupied with dislodging moderate rebels from key checkpoints and northern towns as they are with fighting the regime.