From their website, "The Violence Project is a 501(c)(3) nonprofit, nonpartisan research center dedicated to public criminology and data-driven violence prevention."

Resources for statistics educators include...
--graphs of data (https://www.theviolenceproject.org/key-findings/),
--a data base (https://www.theviolenceproject.org/mass-shooter-database/),
--a Methodology page (https://www.theviolenceproject.org/methodology/)