Mr Zilk, whose hand was damaged by a letter bomb sent by Austrian neo-fascists five years ago, said the charge was absolutely groundless.

ECONOMIST: Czech Republic

Danish police think a man hurt in a blast was making a letter bomb to use against a newspaper which published cartoons of the Prophet Muhammad.

BBC: Bomb suspect 'targeted' Danish paper Jyllands-Posten

In 2011, a Danish court sentenced a Chechen-born man to 12 years in prison for preparing a letter bomb that exploded as he was assembling it in a Copenhagen hotel.

NPR: Russia's Chechnya Has Seen Decades Of War, Terror

On September 19th 1972 a letter-bomb in London killed Ami Shachori, an Israeli diplomat.

ECONOMIST: A history of parcel bombs

Nine people have been injured by the letter bombs, including four workers who were hurt when a bomb exploded at the Driver and Vehicle Licensing Authority centre in Swansea.

BBC: NEWS | UK | Letter bomb suspect is arrested

He signed the letter to Franklin Roosevelt warning that it may be possible to build an atom bomb, and the letters of his famed equation relating energy to mass hover in our minds when we picture the resulting mushroom cloud.

NPR: Einstein: Relatively Speaking, a Complicated Life

When the bomb was built, however, he was among the Manhattan scientists who put their names to a letter to President Truman asking that the Japanese be given a demonstration and a chance to surrender before the device was used on a city.

ECONOMIST: Glenn Seaborg