Damning evidence was found when US special forces killed Islamic State (ISIS) leader Abu Sayyaf in May, revealing that NATO-member Turkey has in fact been collaborating with the brutal jihadists.
The British Guardian reported on Sunday that when Abu Sayyaf's compound was raided in eastern Syria, it was discovered that Turkey is the main buyer of smuggled ISIS oil which was managed by Abu Sayyaf to economically prop up the terror group.
The report quoted a senior Western official, who told the Observer that the findings at the compound showed direct deals between Turkish officials and ISIS leaders is "undeniable."
"There are hundreds of flash drives and documents that were seized there,” the official said. "They are being analyzed at the moment, but the links are already so clear that they could end up having profound policy implications for the relationship between us and Ankara."
"We are at a phase in this war where things that have been in the shadows for a long time are now being exposed to daylight. Hezbollah is dominant in the west of Syria, and the Turkish role, however you wish to define it, is also becoming clearer. This is an important time for them. Will they now see ISIS as a threat to their own sovereignty? ...A lot of damage has been done from this."
ISIS was allowed to transform into a major regional power thanks to an estimated $1-4 million a day in oil sales during a period of six months beginning in late 2013.
While Abu Sayyaf's oil smuggling operation has been cut in scope, tankers still carry crude oil from the refineries captured by ISIS to the Turkish border.
One ISIS member said in the report of his group that "they need the Turks. I know of a lot of cooperation and it scares me. I don’t see how Turkey can attack the organization too hard. There are shared interests."
He added that the US-led airstrike campaign has done nearly nothing in limiting ISIS.
Strikes on ISIS - only meant to harm Kurds?
Turkey has openly given its support to other jihadi groups fighting Syrian President Bashar al-Assad, such as Ahrar al-Sham that largely follows Al-Qaeda's ideology, as well as the Al-Qaeda linked Nusra Front.
"The distinctions they (Turkey) draw (between opposition groups - ed.) are thin indeed,” said the western official. “There is no doubt at all that they militarily cooperate with both.”
Evidence of that cooperation has come in the form of a video showing how the Turkish government smuggled weapons in to Syria to aid jihadist forces, in a botched attempt in which agents were arrested on the border.
Just last Thursday after a deadly suicide bombing blamed on ISIS, Turkey finally ended its long opposition to attacking ISIS, opening an airbase to US usage and launching airstrikes against the jihadists.
However, it also has used the opportunity to declare war on Kurdish forces in Syria and Turkey, with experts predicting that Turkish President Recep Tayyip Erdogan is using the campaign as a pretext to fight the Kurds - particularly after his party lost badly in elections to a pro-Kurdish party.
With the new developments in Turkey's attacks on ISIS, a European official in Ankara said Western diplomats can now talk about ISIS with the Turks "as long as we describe them as ‘those who abuse religion.'"
"This isn’t an overhaul of their thinking. It’s more a reaction to what they’ve been confronted with by the Americans and others. There is at least a recognition now that ISIS isn’t leverage against Assad. They have to be dealt with.”