ANTAKYA, Turkey — Free Syrian Army Cmdr. Jamil Radoon’s assassination Aug. 26 hit hopes for lessened Islamist hegemony among opposition forces hard.

While this incident took place in the southern Turkish town of Antakya, it also raised questions about security across the border. The blast from explosives placed under his car hit only Radoon, who died in hospital shortly afterward. No group or individual has claimed responsibility as of yet.

The commander and defected colonel had led a force of a few thousand fighters in his group Suqour al-Ghab, which operated mostly in his home region of northern Hama and had cooperated with others in the Jaish al-Fatah operations center on the front lines there.

He had, however, long felt threatened by a number of other groups within Jaish al-Fatah, including the local al-Qaeda affiliate Jabhat al-Nusra. Recipients of US TOW armor-piercing anti-tank systems — which other commanders working in the area told Al-Monitor had proven decisive in recent advances there — Radoon’s group was "seen as competition," as one member of an FSA political office put it, due to their effectiveness. Jabhat al-Nusra receives many fighters and support on the basis of its reputation for being the strongest fighting force on the ground.