Yehoshua Cohen was a leading member of Lehi, a Zionist militant group, who assassinated United Nations envoys Folke Bernadotte and André Sérot on September 17, 1948. Cohen was never charged for his role in the assassination, and was one of the founders of the Sde Boker kibbutz in the Negev Desert, where David Ben-Gurion later lived. While Ben-Gurion lived at Sde Boker, he and Cohen became close friends.

Lehi, often known pejoratively as the Stern Gang, was a Zionist paramilitary militant organization founded by Avraham ("Yair") Stern in Mandatory Palestine. Its avowed aim was to evict the British authorities from Palestine by use of violence, allowing unrestricted immigration of Jews and the formation of a Jewish state. It was initially called the National Military Organization in Israel, upon being founded in August 1940, but was renamed Lehi one month later. The group referred to its members as terrorists and admitted to having carried out terrorist attacks.