Sheikh Mujibur Rahman, the founding president of Bangladesh, was assassinated along with most of his family members during the early hours of 15 August 1975 by a group of Bangladesh Army personnel who invaded his residence at 32 Dhanmondi as part of a coup d'état. Commerce Minister Khondaker Mostaq Ahmad immediately took control and proclaimed himself head of an interim government from 15 August to 6 November 1975, before being succeeded by Chief Justice Abu Sayem. The event marked the first direct military intervention in Bangladesh's civilian administration, and 15 August was later observed as National Mourning Day under the government of Sheikh Hasina.
According to court testimony and later accounts collected in reporting on the case, Major Sayed Farooq-ur-Rahman, Khandaker Abdur Rashid, Shariful Haque Dalim, Mohiuddin Ahmed, Rashed Chowdhury, A. K. M. Mohiuddin Ahmed, Mohammad Bazlul Huda, and S. H. M. B. Noor Chowdhury were identified as alleged participants in the conspiracy to topple the government. Those accounts said they had previously opposed the ruling Bangladesh Krishak Sramik Awami League (BAKSAL) one-party system and viewed Mujib's government as too subservient to India and a threat to the military. On the morning of 15 August, the alleged conspirators divided into groups; according to those accounts, one group, comprising members of the Bengal Lancers of the First Armoured Division and the 535th Infantry Division under Major Huda, used tanks to create roadblocks and attacked Mujib's residence. Army chief K. M. Shafiullah stated he was caught unaware and was unable to stop the coup, describing a final telephone call in which Mujib told him his house had been attacked and asked for troops to be sent.
A domestic worker at the residence, Abdur Rahman Sheikh Roma, later testified in court about the events of that night, describing the household members present—including Mujib, his wife Begum Mujib, and their youngest son Sheikh Russel—and the moment gunfire was heard approaching the house after Begum Mujib reported an attack on the nearby residence of Abdur Rab Serniabat.
Background factors cited in connection with the assassination include controversy over the Jatiya Rakkhi Bahini militia and its funding relative to the regular army, tension between army officers over promotion decisions (notably the appointment of Shafiullah over Ziaur Rahman as army chief), allegations of nepotism and corruption involving Mujib family members, a left-wing insurgency led by the Jatiya Samajtantrik Dal and its armed wing from 1972–1975, opposition rhetoric portraying Mujib's government as subservient to India, tensions between secularist state policy and Islamist political currents, critical newspaper coverage, the 1974 famine in North Bengal, and the establishment of BAKSAL as a one-party state in June 1975 following the banning of other political parties and the independent press. An unsuccessful assassination attempt using grenades reportedly occurred on 21 May 1975 as Mujib returned to his residence, an incident that was not publicized at the time on government instruction.
Intelligence warnings were reportedly given to Mujib prior to the assassination, including from India's Research and Analysis Wing chief Rameshwar Nath Kao, from U.S. officials including then-Ambassador Davis Eugene Boster, from Canadian Prime Minister Pierre Trudeau via an intermediary, and from Bangladesh's own Foreign Secretary Fakhruddin Ahmad, according to accounts collected in the case's Wikipedia reference material.