Newly leaked handwritten orders show the ISIS has been plotting with the Assad Government for years in deals over oil, battleground, and over the ancient city of Palmyra.
The leaked documents obtained by Sky News show Syrian Government forces, backed by Russian air strikes, took back control of IS’s most important strongholds in Palmyra in one of the biggest deals negotiated.

An investigation by the British broadcaster uncovered secret files revealing the Syrian regime ordered the Islamic State to hand the ancient city of Palmyra back to government forces.
Two months later, IS recaptured the city and drove out government forces in days before demolishing some of the best-known monuments in the UNESCO world heritage site.
Not only could the Syrian regime be torn apart if reports of this collusion was confirmed, but Russia could also be implicated amid the controversy.
Sky News the ISIS handed Palmyra back to Syrian government forces as part of a series of agreements going back years.
New letters obtained by the broadcaster are copies of handwritten orders sent from IS headquarters.
They reveal deals between the Assed regime and IS chiefs to: withdraw weapons from Palmyra; trade oil for fertiliser; and evacuate some areas by IS forces before the Syrian army attacked.
During the 18-month investigation, contacts were maintained with a Free Syrian Army group working to smuggle defectors away from IS across the border to Turkey.
The investigation uncovered how the militant group has been training foreign fighters to attack Western targets for longer than security services had suspected, the broadcaster revealed.
It confirmed fears a network of sleeper cells exists across Europe, planning further Paris and Brussels-style terror attacks.

Source: Yahoo7 News, 5 May 2016