Although the police knew about ISIS member Yakub Şahin's attempt to purchase ammonium nitrate to make bombs 10 days prior to the attack, they turned a blind eye to it, according to documents that emerged in 2019.

Lawyers representing the families of the victims of the 2015 Ankara bombing have filed a criminal complaint against officials of the Gaziantep Security Directorate over their negligence to prevent the deadly bombing.

The lawyers said in their petition that although Gaziantep Security Directorate officials had located ISIS member Yakub Şahin prior to the Ankara bombing, they did not detain him.

The lawyers said documents that surfaced in 2019 reveal that police knew Şahin tried to purchase ammonium nitrate to make bombs 10 days prior to the attack.

According to these documents, a fertilizer salesman reported to police in Gaziantep's Nizip district on two men who refused to present his identification while attempting to purchase nitrates, as required by law.

The police's investigation at the time revealed one of the men to be Şahin, who later escorted suicide bombers from Gaziantep to Ankara.

This evidence came to light when the missing files were found among the folders in a cupboard in the prosecutor's office in 2019.

The lawyers said that despite the existence of this information on Şahin, Gaziantep police turned a blind eye to it.

“But during that period, it was known that ISIS was conducting suicide attacks one after another and these actions were organized from Gaziantep. The fact that this tip-off was not taken seriously makes us think that the massacre's perpetrators were not touched on purpose,” said the lawyers.

They further noted that the negligence occurred even though Gaziantep Security Directorate had been previously monitoring Şahin's actions.

“If Yakub Şahin had been caught by taking the tip-off on him into account, maybe 10 October Ankara massacre would not have happened,” the lawyers said, adding that the Gaziantep Security Directorate's failure of action constitutes “an explicit crime.”

The Ankara bombing was carried out on Oct. 10, 2015 by ISIS and killed 103 people, with hundreds more injured. The attack occurred in central Ankara near the city’s main railway station, where two bombs exploded at a “Labor, Peace and Democracy” rally that was organized and attended by a variety of leftist and pro-worker groups, including labor unions and the pro-Kurdish People’s Democratic Party (HDP). The attacks were carried out by two young men affiliated with ISIS networks in Turkey.