A Thessaloniki court today found the guards at the northern Nigrita Prison guilty of torture that caused grievous bodily harm.
But it ruled that the April 2014 assault did not trigger the fatal heart attack Albanian Ilie Kareli, 42, later suffered in his cell. All 12 were freed pending their appeal trial.
The court accepted a coroner's testimony that Kareli, a convicted robber, had suffered from a serious, previously undetected heart condition.
Kareli had been just transferred to Nigrita from another jail, where he allegedly killed a guard after being refused temporary release to visit his critically ill mother.