In May 2013, media reported that Turkish special service officers arrested members of Syrian opposition group who were in possession of two kilograms of sarin.
Later on when the court established that the materials they were trying to obtain could in fact be used to produce sarin, a warrant for the arrest was issued.
The case sparked political controversy when the deputy of the Turkish opposition Republican People's Party (CHP) Eren Erdem said in an interview with RT that Turkey knew about Islamic State-bound shipments of deadly sarin gas passing through its territory.
Eren Erdem was accused of treason by Ankara's top prosecutor and criminal investigation was opened against him.
The prosecutor of the case involving the five Turkish suspects recently denied Erdem's accusations in a statement, saying the Turkish suspects were released because they were not found to be in possession of the materials used for sarin production, while rejecting the idea that the justice minister pressured him into bringing the case to a close immediately.
Two CHP deputies said that the Turkish government was out to get Eren Erdem and had launched a lynching campaign against the deputy.
Republican People's Party (CHP) deputy Ali Şeker stated that Turkish authorities must answer questions in connection with the incident.