"On Tuesday, we, Celik's lawyers, applied to an Izmir court with a petition to reduce or cancel the prison term for the failure to return to prison," Ustundag told reporters.
The lawyer added that the Izmir prosecutor's office resumed the investigation into Celik's involvement in the killing of Russian Pilot Oleg Peshkov and Naval Infantry soldier Alexander Pozynich, who was killed during rescue operation to retrieve the Russian pilots after the Su-24 downing.
The Russian combat plane was shot down by a Turkish F-16 fighter jet over Syria and fell 2.5 miles from the Turkish border in November. The crew of the plane ejected and one of its pilots, Peshkov, was shot from the ground, while the second pilot survived and was later rescued.
Celik was arrested alongside 13 others in the Turkish city of Izmir in April on charges of illegal gun possession, for which Celik was being tried as there was not enough proof of his participation in the murder.