The public prosecutor claimed on Friday that the detainees had relations with the al-Qaeda-linked groups of al-Nusra Front and Ahrar al-Sham Brigades and were in Turkey to produce chemical weapons for them.

The prosecutor completed his indictment as part of the probe into the chemicals seized in the southern city of Adana, located some 150 kilometers (93 miles) from the border with Syria, in late May.

Citing transcripts of several phone conversations between the suspects, the indictment said that a 35-year-old Syrian citizen, identified as Hytham Qassap, established a connection with a network in Turkey in order to procure chemical materials for the terrorist groups fighting in Syria.

The indictment rejected the suspects’ claims about their unawareness of the chemical materials they tried to obtain.

“The suspects have pleaded not guilty saying that they had not been aware the materials they had tried to obtain could have been used to make sarin gas. Suspects have been consistently providing conflicting and incoherent facts on this matter,” the indictment said.

According to the prosecutors, Turkish chemical dealers told the prime suspect Qassap that two of the eight chemicals he was trying to acquire were subject to state approval.

The indictment says Qassap confessed that he moved to the city of Antakya following the instructions of the leader of al-Qaeda-linked Ahrar al-Sham Brigades, Abu Walid.

“After I arrived in Antakya, other rebel groups had come into contact with me. While some had asked me for medicine and other humanitarian aid supplies, others wanted to obtain military equipment,” he told prosecutors.

The investigation was launched after security forces received a tip suggesting that some anti-Syria militants were looking to procure materials that could be used to produce chemical weapons.

Qassap and five Turkish suspects are under arrest while five others have been released.  Sarin has been classified as a weapon of mass destruction in UN Resolution 687.