|This article needs additional citations for verification. (June 2012)|
A letter bomb, also called parcel bomb, mail bomb or post bomb, is an explosive device sent via the postal service, and designed with the intention to injure or kill the recipient when opened. They have been used in Israeli targeted killings and in terrorist attacks such as those of the Unabomber. Some countries have agencies whose duties include the interdiction of letter bombs and the investigation of letter bombings. The letter bomb may have been in use for nearly as long as the common postal service has been in existence, as far back as 1764 (see Examples).
Letter bombs are usually designed to explode immediately on opening, with the intention of seriously injuring or killing the recipient (who may or may not be the person to whom the bomb was addressed). A related threat is mail containing unidentified powders or chemicals, as in the 2001 anthrax attacks.
Letter-bombs, along with anti-personnel mines, are typical examples of subject-matter excluded from patentability under the European Patent Convention, because the publication or exploitation of such inventions are contrary to the "ordre public" and/or morality (Article 53(a) EPC).
- One of the world's first mailbombs is mentioned in the 18th century diary of Danish official and historian Bolle Willum Luxdorph. His diary mainly consists of concise references to news from Denmark and abroad. In the entry for January 19, 1764 he writes the following: Colonel Poulsen residing at Børglum Abbey was sent by mail a box. When he opens it, therein is to be found gunpowder and a firelock which sets fire unto it, so he became very injured. The entry for February 15 same year says: Colonel Poulsen receives a letter in German, [saying] that soon the dose will be increased. It is referring to the dose of gunpowder in the box. The perpetrator was never found. In a later reference Luxdorph has found a mention of a similar bomb being used, also in 1764, but in Savona in Italy.
- June 1889: Edward White, formerly an artist at Madame Tussauds, was alleged to have sent a parcel bomb to John Theodore Tussaud after being dismissed.
- August 20, 1904: A Swedish man named Martin Ekenberg sent a mailbomb to businessman Karl Fredrik Lundin in Stockholm. It was a box loaded with bullets and explosives.
- In 1915, Vice President of the United States Thomas R. Marshall was the target of an assassination attempt by letter bomb.
- In 1946, several British high officials, including Sir Stafford Cripps, Ernest Bevin, and Anthony Eden received letter bombs apparently sent by the extreme Zionist Stern Gang.
- In 1947, several letter bombs were sent to President Harry Truman in the White House. They were intercepted by White House mail room workers, who were on alert because of the letter bombs to British officials. These also were claimed by the Stern Gang.
- August 30, 1958: A parcel bomb sent by Ngo Dinh Nhu, younger brother and chief adviser of South Vietnamese President Ngo Dinh Diem, failed to kill King Sihanouk of Cambodia.
- In 1961 the Nazi war criminal Alois Brunner received a letter bomb that caused the loss of an eye. In 1980 another letter bomb cost him the fingers of his left hand. Two Damascus postal workers were killed. The senders are unknown but some suspect the Israeli intelligence agency Mossad.
- In the 1960s, 1970s and early 1980s, several terrorist organizations in Argentina such as Montoneros and ERP included letter bombs into their weaponry.
- On 28 December 1977, in Malta, Karen Grech, age 15, was killed when she opened a letterbomb addressed to her father Edwin Grech. On the same day, another bomb was sent to Labour MP Dr. Paul Chetcuti Caruana, but it did not detonate.
- Theodore Kaczynski, the "Unabomber", killed three and injured 23 in a series of mailbombings in the United States from the late 1970s to the early 1990s.
- Ruth First, a South African communist anti-apartheid activist was killed by a parcel bomb mailed by the South African government to her home in Mozambique, on August 17, 1982.
- In August 1985, a woman in Rotorua, New Zealand, Michele Sticovich, was instantly killed and a close friend of hers seriously injured after she opened a parcel addressed to her containing a number of sticks of gelignite. Mrs Sticovich's estranged husband, David Sticovich, was arrested and ultimately pleaded guilty to her murder.
- On October 19, 1986, Dele Giwa, a Nigerian journalist and editor of the Newswatch magazine was killed with a mail bomb, claimed to be sent by Nigeria's former dictator, Gen. Ibrahim Babangida. The general has never admitted complicity, remaining mute on the issue.
- On December 16, 1989, Robert Smith Vance, a U.S. federal judge, was killed instantly upon opening a letter bomb in the kitchen of his home in Birmingham, Alabama, with his wife, Helen, seriously injured. Walter Leroy Moody was later convicted of killing both Vance and Georgia attorney Robbie Robertson by use of letter bombs delivered through the mail.
- Franz Fuchs, Austrian mailbomber, killed four and injured 15 with mailbombs and improvised explosive devices in the mid-1990s.
- Singer Björk was sent a letter bomb charged with explosives and sulfuric acid by fan Ricardo López in 1996. The bomb did not reach Björk, having been randomly intercepted by London Police.
- In February 2007, a series of mailbombings in the United Kingdom injured nine people, though none of them were critically hurt.
- In January and February 2007, a bomber calling himself "The Bishop" sent several unassembled bombs to financial firms in the United States, and was arrested in April 2007.
- In August 2007, a Lebanese immigrant, Adel Arnaout, was charged in connection with a letter bomb ring in the Toronto-Guelph area of Ontario, Canada; he was allegedly responsible for injuring 1 person. He was also allegedly responsible for the precautionary closing of a portion of the Don Valley Parkway in Toronto on August 31, 2007.
- In April 2011 Neil Lennon and two high-profile fans of Celtic F.C. were sent parcel bombs.
- In February 2014, a series of seven letter bombs were sent to Armed Forces recruitment offices in the United Kingdom, which bore all the hallmarks of Northern Ireland-related terrorism.
- In September 2015, at least six people were killed and dozens injured in explosions at 15 locations in Liucheng County in China's Guangxi Zhuang Autonomous Region. The explosives were reportedly concealed inside express delivery packages. 
- Father Michael Lapsley was sent a letter bomb in 1990 by the Civil Cooperation Bureau, which was hidden inside two religious magazines. He lost both hands and the sight in one eye in the blast, and was seriously burnt.
- Bomb threat
- Email bomb
- Luke Helder The Midwest Pipe Bomber (bombs were planted in mailboxes, not sent through the Postal Service).
- *(USPIS) In the United States, the Postal Inspection Service is responsible for investigating the use, or threat of use, of letter bombs, harmful chemicals and dangerous devices sent through the postal system.
- Guidelines for Examination in the EPO, section g.ii.4.1 , "Matter contrary to "ordre public" or morality".
- Eiler Nystrøm(ed.) - Luxdorphs Dagbøger, volume I, p. 207 & 209, Copenhagen, 1915
- Luxdorphs Dagbøger, volume I, p. 293. The reference Luxdorph mentions is this: Theatrum Europæum, tome XI, p. 745 column 2, fin
- "The Times". 1889-07-20. p. 6.
-  (Swedish)
- Smith, Ira R. T.; Morris, Joe Alex (1949). Dear Mr. President... The Story of Fifty Years in the White House Mail Room. pp. 229–230.
- Catherine Desplanque, Petite biographie d'Alois Brunner/
- "Alois Brunner". Trial-ch.org. Retrieved 2012-11-09.
- "Former top Roturua cop dies". 3 News. November 22, 2009. Retrieved October 14, 2011.
- "Mail bombs lay ruin to Chinese county as 7 killed, dozens injured in 17 sites across Guangxi’s Liucheng". South China Morning Post. September 30, 2015. Retrieved October 1, 2015.