Former Turkish police chief Ömer Köse, who has been imprisoned since 2014 due to his role in the December 2013 graft probes that implicated high-level government officials, was physically attacked by guards in his prison cell in Tekirdağ, the TR724 news website reported.
The incident reportedly took place last Wednesday after Köse got involved in an argument with a guard, after which the guard came back with four colleagues and started beating him up. Four guards restrained Köse while one hit him.
Köse filed a criminal complaint about the incident, according to the report.
For the last two years, he has been held in solitary confinement.
Köse was one of the police officers who took part in a bribery and corruption investigation in connection with state-owned Halkbank that shook the country in December 2013. The probe implicated, among others, family members of four cabinet ministers as well as the children of then-Prime Minister Recep Tayyip Erdoğan.
Despite the scandal resulting in the resignation of all of the cabinet members, the probe file was dropped after prosecutors and police chiefs were removed from the case. Erdoğan, government officials and the pro-government media have described the investigation as an attempt to overthrow the government.