A 36-year-old man, being held in custody for drug possession, was burned alive in his cell yesterday and three police officers were treated for smoke inhalation after the man set fire to his mattress at a jail in Ptolemaida, northern Greece, police said. The prisoner had piled two mattresses on top of each other at the entrance to his cell, making it difficult for authorities to rescue him even though they immediately called the fire brigade. Five minutes after the fire broke out, police cleared the area and rushed the man by ambulance to the hospital where he was pronounced dead. The three police officers were also taken to the hospital after they suffered breathing problems due to smoke inhalation. Authorities have launched an investigation into the exact causes of the incident.