Turkish prosecutors have summoned the screenwriters of the TV series Kurtlar Vadisi Pusu for questioning as part of a renewed investigation into the death of former senior intelligence official Kasif Kozinoglu.

Axar.az reports, citing Turkish media, that Kozinoglu, a former senior official at Turkiye’s National Intelligence Organization (MIT), died in prison in November 2011 while being held in the Ergenekon case. His grave was recently opened, and forensic examinations were conducted to determine whether he died of natural causes or was killed.

Screenwriters Raci Sasmaz, Bahadir Ozdener and Cuneyt Aysan will testify as persons with information in the investigation.

The summons relates to similarities between Kozinoglu and a character named “Kasifoglu” in Kurtlar Vadisi Pusu. The fictional character was an MIT officer who was imprisoned and later killed.

The investigation has already resulted in four arrests, according to the report.