The Islamic State in Iraq and the Levant group has publicly executed a Syrian it accused of planting tracking devices for deadly government air strikes, according to the SITE intelligence group.
SITE posted footage of the accused being paraded before a crowd but the video deliberately freezes at the point an ISIL fighter pulls his head back and holds a knife to his neck.
After the execution, in Syria's northern Aleppo province, the fighters paraded the body of the accused on a cross.
According to Al-jazeera ISIL claimed that that more than 190 people had been killed in the air strikes that the man had abetted.
In October and November, the Syrian government sharply intensified its air strikes on areas held by ISIL or other rebel groups.
In just 40 days, about 2,000 strikes killed more than 500 people, the Britain-based Syrian Observatory for Human Rights said.
Some of the deadliest hit the ISIL "capital" of Raqqa on November 25, killing at least 95 people, but air strikes have also hit the group in the eastern part of Aleppo which they control.
ISIL has earned drawn the world's attention with its release of video footage of its executions of Western hostages, captured soldiers and civilians accused of breaching its version of Islamic law.