Updated

Greece's most wanted bank robber — a man who deeply embarrassed authorities by escaping from prison twice by helicopter — was involved in a militant bombing that killed a police officer last year, officials said Tuesday.

Greek police have issued an arrest warrant for murder and membership of a terrorist group against Vassilis Paleokostas, who has been on the run since his second daring escape from a maximum security Athens prison in 2009.

Paleokostas' fingerprints were found on a parcel bomb that exploded in the public order ministry last summer, killing ministerial aide Giorgos Vassilakis, according to the police statement.

The bombing was claimed by a group that used far-left rhetoric but did not name itself. Two policemen and a journalist have been killed in the past two years as Greece suffered an increase in attacks by radical anarchists and far-leftists.

The spike in political violence followed the fatal police shooting of an Athens teenager in 2008, which sparked days of rioting in major Greek cities. Militants' anger was also fueled by harsh government austerity measures taken to heal the barely solvent country's debt crisis.

Paleokostas' older brother, Nikos, is also a convicted bank robber now behind bars. The siblings have been hailed by many as modern Robin Hoods who shared their loot with the poor and allegedly sent cash payments to owners of any cars they commandeered.

Vassilis Paleokostas, 45, first escaped from Korydallos prison in Athens — together with an Albanian murderer — in a rented helicopter hijacked by accomplices in 2006. Both were recaptured, but later made a complete mockery of Greek prison security by using the same trick to escape in 2009.

Although the Albanian, Alket Rizaj, was arrested months after the second escape, a broad manhunt failed to capture Paleokostas — who, in a letter to the press, accused police of trying to kill him when he fled a roadblock.

Tuesday's police statement said Paleokostas' fingerprints were also found in a stolen vehicle abandoned by unknown gunmen in central Greece after a car chase this week in which a policeman suffered severe gunshot injuries.