Murtala Muhammad was assassinated during an unsuccessful coup d'état in February 1976, and the country went into deep mourning. In less than a year, this man had captured the hearts of many Nigerians. The political shake-up and the decisive leadership in the midst of rapid economic growth seemed to promise a bright future. In fact, there was considerable opposition to Murtala Muhammad that would have become more pronounced in the succeeding months, but this opposition was stifled under the outpouring of national loss.

The attempted coup reflected dissatisfaction within the military that was unconnected with the larger currents of opposition in the country. Two groups of conspirators were involved in the coup. The first, composed of middle-grade officers, was led by Lieutenant Colonel Bukar Dimka, who was related to Gowon by marriage. Dimka's opposition to Murtala Muhammad was both professional and political. Dimka's group protested demobilization and alleged that the FMG was "going communist." A group of colonels answering to Major General I.D. Bisalla, the minister of defense, waited in the wings for Dimka's group to overthrow the government, and then planned to seize power. Dimka, Bisalla, and thirty-eight other conspirators were convicted after a secret trial before a military tribunal and were executed publicly by a firing squad. Evidence published by the FMG implied that both groups of conspirators had been in communication with Gowon, who was accused of complicity in the plot against Murtala Muhammad. The British government refused to accede to Nigerian demands for Gowon's extradition, however, and protests against the decision forced Britain to recall its high commissioner from Lagos.