Alina Afanaskina - one sister (Dasha)
William Atchison - one older brother (Brentt)
Pekka-Eric Auvinen - one younger brother
Connor Betts - one younger sister (Megan, who was a victim in the shooting)
Robert Bever/Michael Bever (brothers) - five younger siblings (Daniel, Christopher, Victoria, Crystal, and Autumn; Daniel, Christopher, and Victoria were 3 of 5 victims)
Sebastian Bosse - one younger brother and a sister
Martin Bryant - one younger sister (Lindy)
Luiz Henrique de Castro - one older brother
Seung-Hui Cho - one sister
Nikolas Cruz - one younger brother (Zachary) and one older sister (Danielle)
Kimveer Gill - two younger brothers
Eric Harris - one older brother (Kevin)
James Holmes - one younger sister (Chris)
Tomohiro Kato - one younger brother (Yuji)
Kipland Kinkel - one older sister (Kristen)
Dylan Klebold - one older brother (Byron)
Thomas Lane - one younger sister (Sadie)
Adam Lanza - one older brother (Ryan)
Timothy McVeigh - one older sister (Patricia) and one younger sister (Jennifer)
Ethan Blair Miller - one younger brother
Dimitrios Pagourtzos - one younger sister
Stephen Paddock - three younger brothers (Eric, Patrick, and Bruce)
Terry Ratzmann - one sister (Cheryl)
Elliot Rodger - one younger brother (Jazz) and one younger sister (Georgia)
Dylann Roof - two sisters (Morgan and Amber)
Trey Sesler - one older brother (Mark, a victim of the 2012 Waller Killings committed by Sesler)
Brenda Spencer two older siblings, a brother (Scott) and a sister (Teresa)
Randy Stair - one younger brother (Jeremy)
Guilherme Taucci - two younger sisters
Austin Thompson - one older brother (Scott, who was a victim of the shooting)