The Wikipedia article of the day for May 17, 2018 is Ngô Đình Cẩn.
Ngô Đình Cẩn (1911–1964) was a younger brother and confidant of South Vietnam’s first president, Ngô Đình Diệm, who put Cẩn in charge of central Vietnam, stretching from Phan Thiết in the south to the border at the 17th parallel. Based in the former imperial capital of Huế, Cẩn earned a reputation as the most oppressive of the Ngô brothers, operating private armies and secret police that controlled the central region. Cẩn’s influence began to wane after his elder brother Ngô Đình Thục was appointed the Roman Catholic Archbishop of Huế. Thục overshadowed Cẩn and aggressively promoted Catholicism, which led to the banning of the Buddhist flag in 1963 during Vesak, the celebration of the birthday of Gautama Buddha. Cẩn’s forces opened fire on a crowd protesting the ban, killing nine and precipitating the Buddhist crisis and the eventual toppling of the Diem regime in a November 1963 coup. Cẩn was arrested and turned over to the military junta, which executed him in 1964.