The decapitated body of an ISIS emir and a senior member of Islamic State's self-declared police force in Syria was found in the eastern province of Deir al-Zor, the Syrian Observatory for Human Rights said on Tuesday.
The deceased man, who held the rank of deputy "emir" of the al-Hesbah (ISIS Police force) in the province, was an Egyptian national, the UK-based Observatory said.
His decapitated body also showed signs of torture and was found dumped near a power plant in al-Mayadeen city. The killers wrote on his body - "This is evil, you Sheikh" - and put a cigarette in the mouth of the decapitated head.
ISIS has put a ban on smoking in all areas under its control. It was not clear who had carried out the beheading. Residents in the areas controlled by Islamic State have said the group has banned smoking in public.
The Observatory stated in the recent days there havebeen two separate attempts by unidentified assailants on the lives of ISIS militants. In one attempt, a car tried to run over a fighter in the city, while in another, an ISIS fighter was hit by a bike-borne attacker carrying a metal weapon.
All areas under its control are sternly ruled by the archaic principles of Sharia. The group currently is the strongest Islamic organisation in Syria and firmly controls the local populations.
It has also occasionally killed its own members for violating the Sharia law. Dozens of local residents have been beheaded and many stoned by the group for crimes including adultery and blasphemy.
In December, reports had emerged that more the 230 bodies were found in a mass grave in Deir al-Zor province. The bodies belonged to the members of the al-Sheitaat tribe, which had battled ISIS since the start.