Surprisingly, since 2012, Turkish police had been following Durmaz, Bali, and at least 17 others linked to the ISIS cell behind most of the attacks in Turkey. Durmaz eventually set up shop in Gaziantep, managing a handful of warehouses to store supplies before they were shipped into Syria, and a workshop for the manufacture of VBIED and suicide vests—one of which he wore most of the time, right up until he killed himself in a May 2016 police raid.
Despite its intelligence on the Durmaz group, though, the Turkish government failed to crack down on these men and many others until early 2015, choosing instead to passively investigate them for links to global jihadism. In July 2015, Seyh Abdurrahman Alagoz, a 20-year-old man who had previously traveled to Syria with his brother, returned to Turkey to explode a suicide vest—made in Gaziantep—at a gathering of leftists waiting to cross the border to give aid to Kobane, the Kurdish-majority town that resisted an ISIS assault. Thirty-three died. In October 2015, Seyh’s brother and an unidentified, non-Turkish national, carried out the attack on Ankara’s main train station, using a similar device. Now, a third individual, wearing a suicide vest like the others, has carried out another attack in Gaziantep.
The Turkish government has increased border security, and reported crossings to Syria have dropped considerably since early 2015. But the ISIS threat persists. The group responsible for many of the recent attacks has suffered some losses, but many of its core leaders are alive, and reportedly in Syria.
In the wake of the failed coup, Turkey has also effectively handicapped the institutions best-positioned to root out ISIS. Turkish security forces face the impossible task of disrupting and defeating three different sub-state groups: the PKK, ISIS, and suspected followers of Gulen. But the purge of thousands of police officers and members of the judiciary for their alleged links to Gulen have decimated Turkey’s police intelligence organization: 6,500 out of 7,000 personnel have been purged from this body, the law-enforcement institution that would normally be expected to play a role in the ongoing investigation into the latest ISIS attack in Gaziantep. This multitude of factors points to longer-term security challenges for the Turkish government and, by extension, some of the potential political vulnerabilities the AKP now faces.
ISIS remains active in Turkey, and its Turkish members remain committed to carrying out attacks. The infrastructure for future attacks starts in Syria, but also draws on resources from inside Turkey, which places a severe burden on law enforcement to disrupt these networks at a time of major bureaucratic upheaval. The Turkish military has made impressive gains in Jarablus in a short period of time, but the next phase of the battle lies on the other side of the border.