Rosario Borgio (1894 – February 21, 1919) was an early Italian mobster establishing one of the first organized crime operations in the Midwestern United States during the early 20th century. In 1917, as the leader of Akron's Black Hand, he offered gang members $250 for each police officer they killed.

Seung-Hui Cho (; Korean: 조승희; [tɕo sɯŋhi] ; January 18, 1984 – April 16, 2007) was a South Korean mass murderer who perpetrated the Virginia Tech shooting in 2007. Cho killed 32 people and wounded 17 others with two semi-automatic pistols on April 16, 2007, at Virginia Tech in Blacksburg, Virginia.

Pasquale Barra (Italian pronunciation: [paˈskwaːle ˈbarra]; 18 January 1942 – 27 February 2015) was an Italian Camorrista who was a senior member and hitman for the Nuova Camorra Organizzata (NCO), a Camorra organisation in Naples. Barra has the distinction of being the first NCO member to become a pentito, when he decided to collaborate with Italian Justice in 1982.

David Parker Ray (November 6, 1939 – May 28, 2002), also known as the Toy-Box Killer, was an American kidnapper, torturer, serial rapist, and suspected serial killer. Ray kidnapped, raped, and tortured an unknown number of women over many decades at his trailer in Elephant Butte, New Mexico, occasionally assisted by accomplices including his daughter Glenda Jean Ray and partner, Cindy Hendy.