Roger Reece Kibbe (May 21, 1939 – February 28, 2021) was an American serial killer and rapist known as the "I-5 Strangler". Kibbe found all but one of his victims on freeways around Sacramento, California.

Giuseppe Giacomo Gambino (Palermo, 21 May 1941 – Milan, 30 November 1996), also known as u tignusu (the bald one), was a member of the Mafia and head of the San Lorenzo mandamento. Giuseppe Giacomo Gambino was considered the deputy of Totò Riina since the 1970s and the two frequently traveled together.

Richard Wayne Snell (May 21, 1930 – April 19, 1995) was an American white supremacist convicted of killing a pawn shop owner whom he mistook for a Jew and a black police officer in Arkansas on November 3, 1983, and June 30, 1984, respectively. Snell was sentenced to death for one of the murders and executed by lethal injection in 1995.

Francisco García Escalero (24 May 1948 – 19 August 2014) was a Spanish serial killer convicted for the murders of at least 11 individuals between 1987 and 1994. He also practiced necrophilia and cannibalism.

Angelo Bruno (born Angelo Annaloro, Italian: [ˈandʒelo annaˈlɔːro]; May 21, 1910 – March 21, 1980) was a Sicilian-American mobster who was boss of the Philadelphia crime family for two decades until his assassination. Bruno was known as "The Docile Don" due to his preference for conciliation over violence, in stark contrast to his successors.

Mengistu Haile Mariam (Amharic: መንግሥቱ ኀይለ ማርያም, pronunciation: [mənɡɨstu haɪlə marjam]; born 21 May 1937) is an Ethiopian former politician, revolutionary, and military officer who served as the head of state of Ethiopia from 1977 to 1991. He was General Secretary of the Workers' Party of Ethiopia from 1984 to 1991, chairman of the Derg—the Marxist–Leninist military junta that ruled Ethiopia—from 1977 to 1987, and president of the People's Democratic Republic of Ethiopia (PDRE) from 1987 to 1991.

Jeffrey Lionel Dahmer (; May 21, 1960 – November 28, 1994), also known as the Milwaukee Cannibal or the Milwaukee Monster, was an American serial killer and sex offender who killed and dismembered seventeen men and boys between 1978 and 1991.