The BSO is notorious for the kidnap and murder of eleven Israeli athletes and officials, and the murder of a German police officer, during the 1972 Olympic Games in Munich, Germany.
In his book Stateless, Salah Khalaf (Abu Iyad), Arafat's chief of security and a founding member of Fatah, wrote that: "Black September was not a terrorist organization, but was rather an auxiliary unit of the resistance movement, at a time when the latter was unable to fully realize its military and political potential. The members of the organization always denied any ties between their organization and Fatah or the PLO."
Abu Iyad's claim was contradicted by Mohammed Daoud Oudeh, also known as Abu Daoud, a BSO operative and former senior PLO member, who, according to a 1972 article in the Jordanian newspaper Al-Dustur, told Jordanian police: "There is no such organization as Black September. Fatah announces its own operations under this name so that Fatah will not appear as the direct executor of the operation." A March 1973 document released in 1981 by the U.S. State Department seemed to confirm that Fatah was Black September's parent organization.
According to American journalist John K. Cooley, the BSO represented a "total break with the old operational and organizational methods of the fedayeen. Its members operated in air-tight cells of four or more men and women. Each cell's members were kept purposly ignorant of other cells. Leadership was exercised from outside by intermediaries and 'cut-offs' [sic]", though there was no centralized leadership (Cooley 1973).
Cooley writes that many of the cells in Europe and around the world were made up of Palestinians and other Arabs who had lived in their countries of residence as students, teachers, businessmen, and diplomats for many years. Operating without a central leadership (see Leaderless resistance), it was a "true collegial direction" (ibid). The cell structure and the need-to-know operational philosophy protected the operatives by ensuring that the apprehension or surveillance of one cell would not affect the others. The structure offered plausible deniability to the Fatah leadership, which was careful to distance itself from Black September operations.
Fatah needed Black September, according to Benny Morris, professor of history at Ben-Gurion University. He writes that there was a "problem of internal PLO or Fatah cohesion, with extremists constantly demanding greater militancy. The moderates apparently acquiesced in the creation of Black September in order to survive" (Morris 2001, p. 379). As a result of pressure from militants, writes Morris, a Fatah congress in Damascus in August–September 1971 agreed to establish Black September. The new organization was based on Fatah's existing special intelligence and security apparatus, and on the PLO offices and representatives in various European capitals, and from very early on, there was cooperation between Black September and the PFLP (ibid.)
The PLO closed Black September down on September 1973, on the anniversary it was created by the "political calculation that no more good would come of terrorism abroad" according to Morris (ibid. p. 383). In 1974 Arafat ordered the PLO to withdraw from acts of violence outside Israel, the West Bank, and the Gaza Strip.
Recent remarks by Abu Daoud, the alleged mastermind of the Munich kidnappings, deny that any of the Palestinians assassinated by Mossad had any relation to the Munich operation, this despite the fact that the list includes 2 of the 3 surviving members of the kidnap squad arrested at the airport.
Other actions attributed to Black September include:
Dr. Ami Shachori was the agricultural counselor in the Israeli Embassy to the United Kingdom in the London district of Kensington. At the age of 44 he was assassinated in a letter bomb attack on September 19, 1972, perpetrated by Black September.
Eight bombs were addressed to embassy staffers. Four were intercepted at a post office sorting room in Earls Court, but the other four letters made it to the embassy. Three of the letters were detected in the consulate post room but Ami Shachori opened his, believing it contained Dutch flower seeds he had ordered. The resulting blast tore a hole in the desk and fatally wounded Shachori in the stomach and chest.
In Shachori's memory an annual memorial lecture on agriculture in London was established.