Start with high-confidence violence in society books, then narrow by subgenre or adjacent topics.
Parkland
Dave Cullen
Children Under Fire
John Woodrow Cox
Trigger Points
Mark Follman
On Violence
Hannah Arendt
When Violence Is the Answer
Tim Larkin, Little, Brown & Company
The Order of Genocide
Scott Straus
Violence and the Sacred
René Girard
Fist Stick Knife Gun
Geoffrey Canada
Living With Bad Surroundings
Sverker Finnström
A Thousand Ways to Die
Trymaine Lee
The Once and Future Riot
Joe Sacco
One Year in Uvalde
John Quiñones, María Elena Salinas
Bleeding Out
Thomas Abt, Brad Raymond
Unmasked
Andy Ngo
Little Book of Restorative Justice
Howard Zehr
Harbingers
Timothy J. Heaphy
American Carnage
Fred Guttenberg, Thomas Gabor
High Conflict
Amanda Ripley