A Turkish court ordered the arrest of 36 suspects in an expanding investigation into the 2009 helicopter crash that killed prominent politician Muhsin Yazıcıoğlu and five others, with prosecutors investigating alleged involvement in a premeditated killing linked to the Gülenist Terror Group (FETÖ).

The Ankara Chief Public Prosecutor’s Office said the operation was carried out in coordination with the National Intelligence Organization (MIT) and the Ankara Police Department’s Organized Crime Branch as part of the investigation into the crash.

Prosecutors issued detention warrants for 47 suspects accused of participating in premeditated murder as part of alleged FETÖ activities and committing various offenses aimed at preventing authorities from uncovering the truth surrounding the crash.

Authorities carried out searches and seizures at 45 locations across 16 provinces in an Ankara-based operation.

Prosecutors said 10 of the suspects were already in prison, while 33 others were detained on Sept. 25. Five additional suspects were subsequently taken into custody, bringing the number detained in the latest operation to 38.

All 38 suspects were brought before the Ankara Chief Public Prosecutor’s Office. Prosecutors requested the arrest of 36 suspects and judicial control measures for the remaining two.

Yazıcıoğlu, the founder and then-chairperson of the Great Unity Party (BBP), was killed when a helicopter carrying him and five others crashed in the Göksun district of Kahramanmaraş on March 25, 2009.

The other victims were BBP officials Erhan Üstündağ, Yüksel Yancı and Murat Çetinkaya, journalist Ismail Güneş and pilot Mustafa Kaya Istektepe.

The investigation into the circumstances surrounding the crash has continued for more than 17 years.

The Ankara Chief Public Prosecutor’s Office said the latest investigation was continuing on multiple fronts and was being conducted meticulously.