Mehmet Emin Özkan, who was held in Diyarbakır D-Type Prison, was not released despite all warnings and calls.
Özkan was taken to the intensive care unit after his condition worsened on the night of 7 December. Özkan's condition was said to be critical.
Özkan's daughter, Selma Özkan, said that her father was rushed to hospital and added they could not obtain information about his condition.
Özkan's lawyer, Serdar Çelebi, said that Özkan was transferred to the Istanbul Forensic Medicine Institute last week and that he may have caught coronavirus there.
Lawyer Çelebi added that Özkan was kept in the quarantine ward and that the possibility of coronavirus transmission in prison under these conditions is low.
Lawyer Çelebi said: "There is a high probability that he was infected with the virus during his referral to the Istanbul Forensic Medicine Institute."