A 24-year-old Albanian former convict, who police describe as an exceptionally hardened criminal believed to be behind a string of 17 armed robberies on supermarkets in Attica last summer, faced a prosecutor on Saturday following a police raid on an apartment in the eastern district of Zografou. The raid also led to the arrest of another three Albanians believed to have been accomplices to the chief suspect in the robberies last July and August. During most of the robberies, the 24-year-old is alleged to have struck store employees with the butt of his gun. He is also said to have fired his gun into the air in warning on several occasions, though there were no reports of any gunshot injuries. Last April, the suspect received conditional release from Diavata Prison, near Thessaloniki, where he had been serving a 7-year term for theft.