Younger brother and chief political advisor of Diem, Ngo Dinh Nhu ran his brother's regime of secret political movements, the Can Lao. He was assassinated, along with his brother, during the 1963 coup.
Nhu became a warlord and head of secret police while Diem held office. Brutal, exploitative, and corrupt, Nhu was universally hated by the South Vietnamese population.
By May of 1963, unrest had broken out among Buddhists in South Vietnam cities. Buddhists, who composed the majority of the population, complained that the government was restricting their religious freedom and practices. Buddhists leaders accused Diem, a Roman Catholic, of religious discrimination. The growing number of Buddhist priest staged protests, responded to by the government in the form of mass arrests. Diem’s brother, Ngo Dinh Nhu, ordered raids against their temples. These protests aroused the concern of the United States. Kennedy urged Diem to improve his dealings with the Buddhists. He ignored the advice.
The excesses of Nhu were largely responsible for the US backed coup of November 1963, in which both Diem and Nhu were assassinated. Because Diem was celibate, Nhu's wife, Madame Nhu, served as an equally hated de facto first lady.