An important development occurred in the investigation that began with Gülistan Doku's disappearance in Tunceli in 2020. The Erzurum Chief Public Prosecutor's Office took blood, nail, and hair samples from Gülistan Doku's family to compare with DNA samples found in the BMW vehicle used by the detainee Mustafa Türkay Sonel. These samples were sent to the Diyarbakır Forensic Medicine Institution for examination. Within the scope of the investigation, it was determined that the vehicle Sonel used at that time was sold a few years ago and replaced with another vehicle of the same brand, model, and color. It was found that the license plate of the old vehicle was also used on the new vehicle. With the permission of the current owner, the vehicle was taken to the Istanbul Police Department for forensic examination. License Plate Recognition System records show that Sonel and his close friend Umut Altaş used this vehicle on the day Gülistan disappeared. Additionally, in secret witness statements, it was alleged that Gülistan's body might have been transported with this vehicle. The investigation file states that 12 people have been detained, including the then Governor of Tunceli, Tuncay Sonel, and his son. Gülistan Doku's family is calling on the authorities to find their daughter's remains. The investigation continues.