By any standards, it was a humiliating moment for a senior agency of any government. On 19 January, a column of trucks travelling through Turkey's southern province of Adana was stopped by the gendarmerie and forced to reveal the cargo they were carrying. Personnel in the trucks, all apparently belonging to Turkey's secret service, the MIT, were forced to get out and handcuffed. Then the news was released to the Turkish media, accusing the government of sending arms to hardline rebels in Syria. This was not the first time such trucks have been stopped. In fact, there seems to have been a stream of events of this sort. Zaman, the newspaper of the Gulen Movement, a modernist Sufi brotherhood, the leader of which lives in exile in the US, reported that a consignment of munitions on its way to Syria was seized in trucks in Adana on 7 November 2013. On 1 January 2014, Ozcan Sisman, a local prosecutor, was reported to have been overruled by the local governor when he tried to have other trucks searched at Kirikhan. They were on their way to the Oncupınar border crossing, destined for a part of Syria that even at this early date was believed to be under the control of the Islamic State (IS) group. Sisman was forced to resign. The government said the trucks were engaged in humanitarian work and should not be interfered with. They were said to be travelling to help Turkmen communities in Syria. But some Turkmen spokesmen later cast doubt on this. Retribution has followed. Last week, the Turkish authorities announced that ten more officers and soldiers involved in the 19 January 2014 truck search have been arrested and charged and will face trial. These arrests come on top of 47 earlier ones in this case and suggest that a mass trial is being planned. Pro-government news sources, including the Anatolia news agency and the newspaper Yeni Safak, link the arrests to the drive in Turkey to eliminate the Gulen Movement and punish its supporters in government office. Until the prosecution indictments are presented in court, one cannot do much more than hazard a guess about the nature of the evidence this may be based on. But hostility between the Gulenists inside the judiciary and MIT has been visible for some years. On 7 February 2012, an attempt was made by prosecutors believed to be linked to the Gulenists to have Hakan Fidan, head of the MIT, arrested for his behind-the-scenes talks with Kurdish leaders that ultimately led to the ceasefire with the PKK Kurdish movement. From the point of view of the ruling AKP (Justice and Development) Party government, it was the Gulenists who started the feud. At the time when the trucks were being stopped, that feud had reached a crescendo with attempts to arrest leading associates of the government, including the sons of four ministers, on corruption charges. The arrests were reversed, and the prosecutions were dropped. On 12 May this year, the final stage came when the leading prosecutors behind the corruption-case arrests of December 2013 were stripped of their professional licences by Turkey's supreme judicial body, the High Council of Prosecutors and Judges (HSYK). The government evidently views the truck probes over the past two years as part of a failed attempt by the Gulenists to unseat it. And it is giving no quarter. A month ago, the threat from the Gulenists was included in an official secret document regarding strategic dangers to the country. By itself a Sufi movement might not seem to present an obvious strategic danger to Turkey, as opposed, perhaps, to a political challenge. However, the government has recently expanded its accusations against the Gulenists, suggesting that a pact of some sort is emerging between the movement's leader, Fethullah Gulen, and Iran. The fact that the authorities are making a charge of this sort is surprising: Iran and Turkey have maintained fairly good relations, and a recent official visit to Tehran by Turkish President Recep Tayyip Erdogan passed off uneventfully, despite some tough remarks he made before setting off. As for Gulen, he has not shown much sympathy towards Iran in the past. So far as can be discerned, his views on foreign affairs tend to be broadly in line with those of the United States. However, the allegation now is that the ten arrested soldiers belong to an Islamist pro-Iranian organisation called Selam Tevhid (Hail Unity) or the “Jerusalem Army.” This shadowy body is said to be an offshoot of Hezbollah and to have been responsible for the assassination of leading Turkish secularists, including the journalist Uğur Mumcu in the 1990s. Again, it is almost as surprising to find alleged supporters of Hezbollah among the still generally secularist Turkish military as it is to think of Gulen in cahoots with Tehran. Time will show how strong the evidence is. Some may see poetic justice in these accusations. Gulenists formerly inside the judiciary are blamed for launching the massive but shaky conspiracy trials called Ergenekon and Balyoz (Sledgehammer) in which hundreds of senior Turkish military figures were jailed for years on what is now generally regarded as trumped up evidence. However, in the Adana truck search case, the men arrested appear to be mostly very junior figures who were obeying orders from their superiors. They are now being reported in the media as members of Selam Tevhid. Moreover, the arrests have drawn unwelcome publicity to the fact that something was crossing from Turkey into Syria under official auspices and perhaps still is. The border is extremely porous. Turkey's attitude towards IS was unclear in early 2014. It is now firmly unfriendly. On 22 April, for example, Erdogan denounced IS as “a virus which is trying to destroy the umma [Islamic community].” Yasin Aktay, a deputy chairman of the AKP, says that any aid in trucks going into Syria is not for IS but for the opposition Free Syrian Army. Prosecutions such as those of the ten soldiers are probably set to continue, a reminder that high as Syria is on the Turkish authorities' list of priorities, the fight against internal supporters of the Gulen Movement comes even higher. The author writes regularly on Turkish society, politics and history and is finishing a book on the Ottoman Empire in the 19th century.