Theofilou, who was arrested in Athens, has been charged murder, attempted murder, being part of a criminal gang, robbery and illegal possession and use of firearms.
He appeared before a prosecutor on Sunday to answer the charges, which relate to the armed robbery at a branch of Alpha Bank in the town of Naoussa on Paros earlier this month during which 53-year-old Dimitris Michas was shot dead as he tried to stop the robbers.
However, Theofilou is also likely to face charges in connection with the urban guerrilla group Conspiracy of the Cells of Fire. Police say there is DNA evidence linking the 29-year-old with one of the group’s hideouts in Agrinio, central Greece.
Police have taken the unusual step of publishing photographs of the suspect as well as CCTV images from the robbery