Pasquale Galasso (Poggiomarino, May 17, 1955) is a former boss of the Galasso clan, a clan of the Camorra, the Neapolitan crime organization. Since August 1992, he has been a pentito (a criminal turned state witnesses), collaborating with the Italian justice.

Richard Scott Baumhammers (born May 17, 1965) is an American spree killer and white supremacist who committed a racially motivated shooting spree on April 28, 2000, in the metropolitan area of Pittsburgh, Pennsylvania, killing five people and paralyzing one.

Terry Douglas Clark (May 17, 1956 – November 6, 2001) was an American murderer convicted of the murder of nine-year-old Dena Lynn Gore. He was executed by the state of New Mexico by means of lethal injection.

Herberts Albert Cukurs (17 May 1900 – 23 February 1965) was a Latvian aviator and Nazi collaborator. He served as the deputy commander of the Arajs Kommando, a collaborationist unit that carried out the largest mass murders of Latvian Jews during the Holocaust.

David Patrick Roger Lefèvre (born 17 May 1980), known as The Swamp Killer (French: Le Tueur des Marais), is a French serial killer.

Sergey Aleksandrovich Shipilov (Russian: Серге́й Алекса́ндрович Шипи́лов; born 17 May 1959), known as The Velsk Chikatilo (Russian: Вельский Чикатило), is a Russian rapist and serial killer sentenced to life imprisonment for 14 murders and nine rapes. Most of his murders took place in the town of Velsk.

Bartholomew Roberts (17 May 1682 – 10 February 1722), born John Roberts, was a Welsh pirate who was, measured by vessels captured, the most successful pirate of the Golden Age of Piracy. During his piratical career, he took over 400 prize ships, although most were mere fishing boats.

Salvatore "Sammy the Bull" Gravano (born March 12, 1945) is an American former mobster who rose to the position of underboss in the Gambino crime family of New York City before becoming a government witness. As the underboss, Gravano played a major role in prosecuting John Gotti, the crime family's boss, by agreeing to testify as a government witness against him and other mobsters in a deal.