With the minimum of fuss or difficulty, Hayat Boumeddiene, the partner of French Islamist Amedy Coulibaly, crossed the French border into Spain on January 2nd where she boarded a flight from Madrid to Istanbul at around 2.25 pm, five days before the attack on Charlie Hebdo left 12 people dead.
Turkish officials say Boumeddiene spent six days in Turkey accompanied by a man of North African descent, dividing her time between Istanbul and Gaziantep, a city 70km from the Syrian border, before slipping into Syria. It is unlikely she will now be reached or questioned any time soon about her part or Coulibaly's motives for taking part in France's worst terrorist attack in decades.
If Turkish authorities knew when Boumeddiene entered Turkey and left for Syria by using CCTV and tracking telephone calls, as was outlined by Turkey's foreign minister Mevlut Cavus last Monday, why wasn't she stopped?
"We were not aware she was involved in illegal activities [in France]. The French authorities didn't give us any information," said a Turkish official who wished to remain anonymous. "If the French told us about the lady we would have deported her to France. [But] that never happened."
The ease with which she and thousands of other foreigners – some pursuing jihad, others wishing to live a new life in Islamic State’s so-called caliphate – can access northern Syria through Turkey is unsettling for many Western governments. But the reality is that getting into Syria from Turkey undetected is far from difficult.
Flights from a host of European cities to Istanbul often cost as little as €30 during winter months, making the Turkey route more enticing than attempting to enter Syria via Lebanon or Jordan.
Combined, Ataturk International and Sabiha Gökçen airports last year served 42 million international passengers with 17 direct daily flights from London and six every day from Berlin. Boumeddiene flew into Sabiha Gökçen airport on the Asian side of the city before travelling south where Syrian rebels, activists and foreign fighters have set up new, temporary lives.
Istanbul hideouts
It's not only in the Turkish countryside that the effects of the war in Syria can be felt. In a nondescript district of northwest Istanbul, a cafe owner – who asked not to be identified as he has recently been interviewed by police and is fearful for his business – has been renting out his apartment to British Muslims and Pakistani nationals who have gone on to fight for Islamic State in Iraq and Syria. He said they first fly to Istanbul before heading to Syria by bus.
In Levent, the financial district, and in other conservative Istanbul locales such as Bagcilar and Fatih, support for the al-Qaeda-linked group, Jabhat al-Nusra, is thought to be considerable.
A survey conducted in September found that 52 per cent of Turks believed Islamic State received support from inside Turkey. Clashes between students supporting and opposing Islamic State regularly break out on campuses across Turkey.
Turkey’s attractiveness as a route to Syria also stems from Ankara’s policy of allowing Syrian civilians, aid agencies and rebel fighters move freely across its border in 2011 and 2012. Analysts say the ruling AK Party’s policy of tolerating burgeoning extremist groups in Turkey and allowing their entry and exit from Syria during the early stages of the conflict was an attempt to exert influence upon them but that ultimately failed.
As northern Syria turned increasingly lawless in 2013, Turkish authorities struggled to keep up with the surge of war-hardened foreign fighters using Turkey to transport weapons, cash and manpower across a 900km border.
Official crossings
Today only registered refuges and people born in Syria are allowed enter northern Syria through official Turkish border crossings. Smugglers charge as little as €20 per person for illegal entry to Syria, while many without documents cross by traversing rivers and mountains.
Turkey has long been accused of doing little to stop suspected extremists and criminals from entering Syria and Iraq, and only declared Jabhat al-Nusra a terrorist organisation last June.
Since then, some 7,000 individuals from around 80 countries have been “blacklisted”, meaning they are held and deported by Turkish authorities after reaching a border point.