In October of 1991, George Hennard, drove his truck through the plate glass window of Luby's in Killeen, TX. He got out of his truck and opened fire on the customers in the restaurant. He killed 23 people and wounded 27 others. The massacre ended with a shootout between police and Hennard.

Sources:

Luby's shooting - Wikipedia

30 Years Later: Massacre at Luby’s Cafeteria in Killeen (kwtx.com)The Massacre That Turned Texas Into

America's Most Gun-Friendly State (texasmonthly.com)

30 Years Ago, George Hennard Shot and Killed Dozens at a Luby's in Killeen. The Attack Changed Texas Forever. | Dallas Observer

Mass shooter turned a Luby’s into bloodbath 31 years ago (expressnews.com)

Shooting rampage at Killeen Luby's left 24 dead (chron.com)

Oct 17, 1991, page 5 - The News-Messenger at Newspapers.com

Oct 20, 1991, page 102 - Daily Record at Newspapers.com

Oct 20, 1991, page 2 - The Monitor at Newspapers.com

Oct 18, 1991, page 13 - The Brattleboro Reformer at Newspapers.com

George Jo Hennard | Murderpedia, the encyclopedia of murderers