Samir Abd Muhammad al-Khlifawi, a former intelligence officer in Saddam Hussein's air defense force, was behind the Islamic State group's takeover of northern Syria, according to documents uncovered by the German magazine Der Spiegel.

Der Spiegel said that the 31 pages of documents -- including handwritten organizational charts, lists, and schedules -- it had comprised a "blueprint" for the establishment of an Islamic "caliphate" in Syria. Spiegel said that it obtained the documents after lengthy negotiations with the Syrian rebel group the Tawhid Brigade. (Tawhid, however, refused to hand over documents that included a list of spies inside its own ranks.)

The documents were hidden in a house in Tal Rifaat in northern Syria belonging to Khlifawi, who also went under the name Haji Bakr. After his death in January 2014, a single page was smuggled out to Turkey in April of that year.

According to Der Spiegel, Haji Bakr had been part of a small advance party sent by IS from Iraq to Syria in late 2012. Haji Bakr came up with a plan to capture as much territory in Syria as possible and then from there invade Iraq.

The detailed and meticulous plan laid out by Haji Bakr involved recruiting followers in Syria under the guise of opening a Dawah, or missionary center, in a town or village. IS would then select one or two men from the village to act as spies and provide the group with information, such as the names and sizes of local rebel brigades and the names of their leaders.

Other intelligence gathered by the spies included information that could be used as possible blackmail fodder, such as if a particular individual was a criminal, homosexual, or involved in an illicit affair.

Under Haji Bakr's plan, IS also recruited militants, but did not do so from among Iraqi or Syrian fighters. Instead, the group chose to "gather together all the foreign radicals who had been coming to the region since the summer of 2012," Der Spiegel's Christoph Reuter says.

Although the Der Spiegel story does not mention his name, one of the "battle-tested Chechens" recruited by IS in northern Syria was Tarkhan Batirashvili, or Umar al-Shishani, an ethnic Kist on his mother's side from the Pankisi Gorge in Georgia. Batirashvili and his group operated out of the town of Haritan in northern Aleppo Province, and fought together with IS militants in offensives in the area, including at the Menagh air base near the Turkish border. IS recruited Batirashvili, who proved himself unquestioningly loyal and compliant as well as able to supply fighters as willing "cannon fodder," as its military commander in northern Syria.

By the fall of 2013, according to Der Spiegel, IS books listed 2,650 foreign fighters in Aleppo, most of whom were Tunisians and Saudis; Chechens were present in smaller numbers.

According to Der Spiegel, while IS sought to gather intelligence about everyone and everything, the group also wanted to "deceive everyone about its true aims."

In one report found among the Haji Bakr papers, the author had listed all the pretexts the group could use to justify seizing the largest flour mills in northern Syria, including alleged embezzlement and the "ungodly behavior" of mill workers.

"The reality -- that all strategically important facilities like industrial bakeries, grain silos and generators were to be seized and their equipment sent to the caliphate's unofficial capital, Raqqa -- was to be kept under wraps," Der Spiegel wrote.

That IS's Iraqi leadership wanted to conceal the true reason why it was capturing facilities like grain silos and flour mills begs the question of whether rank-and-file militants -- such as the Chechen foreign fighters under Umar al-Shishani -- were aware of IS strategy or whether they were fed the pretexts suggested in the Haji Bakr documents.

Reports from Chechen sources within IS suggest that the latter is possibly the case and that militants sent to take over such facilities believed nothing more than that they were doing so for the good of the people under IS control.

In March 2014, two months after Haji Bakr was killed, a group of Chechen militants fighting alongside IS helped to take over a grain elevator in a village named Sirin near Kobani in northern Syria. The grain elevator had been held by the Kurdish People's Protection Units (YPG). Chechen sources reported at the time that the reason they took over the elevator was because its capture would be "of immense help for the peaceful population of the Islamic State (the areas under IS control) and give a lot of workplaces to Muslims."

-- Joanna Paraszczuk