That was no ordinary Athens bomb that went off at 8.30 pm last Thursday night.
The parcel, addressed to the minister of interior, Michalis Chrysochoidis, was wrapped up to resemble a gift.  When the minister’s assistant, George Vassilakis, tried to prise it open, it exploded and killed him instantly.  The police say the parcel contained half a kilogramme of gunpowder and ammonium nitrate.
Small bombs are not unusual in Athens.
Anarchist and far-leftist groups often place gas canisters and other explosive devices outside banks, government offices and other supposed symbols of capitalism and oppression.  The bombs usually go off in the middle of the night, and, typically, the police receive a warning call a few minutes beforehand. The intention is not to hurt, but to make a defiant statement.
But this brazen attack was something different, and has shocked many people here. In the words of Nikos Xydakis, a columnist for the Kathimerini newspaper, “this parcel bomb did not symbolise passionate protest it was the weapon of cold-blooded killers who make no distinction between their targets”.
Nobody has claimed responsibility, but the Greek press suspects the hand of a group called Revolutionary Struggle.  This is the most active of the various extremist groups that operates in Athens.
In April the police arrested six suspected members of Revolutionary Struggle, and said they had uncovered a large cache of weapons, (which apparently included a rocket-propelled grenade launcher used in an attack on the American embassy in 2007).  So perhaps this group is now trying to send a message, that it is very much alive and kicking.
Revolutionary Struggle, and other groups like it, is following in the footsteps of the most deadly Greek extremist organisation of them all, known as November 17.  Over a period spanning almost three decades, November 17 killed 23 people, including American, British and Turkish officials.  A Marxist group with an anti-American philosophy, it was finally broken up in 2002.
So where do we go from here?
This is a time of social unrest in Greece, as people struggle to cope with deep cuts in public spending, and rising unemployment.
I was surprised when I asked a conservative Athenian friend what he thought of the bombing. “I’m sorry that someone was killed, but I’m glad they let the bomb off, to show how unhappy people are” was his blunt reply.
It’s possible that extremist groups are trying to take advantage of the widespread sense of disillusionment. Minister Chrysochoidis says he will do his utmost to “bring these cowardly murderers to justice”. The pressure is on the Greek police, to find the perpetrators before they strike again.