100 Bullets (Vertigo), book 01: First Shot, Last Call
Brian Azzarello et Eduardo Risso2000

In this dark and intriguing trade paperback, the mysterious Agent Graves approaches ordinary citizens and gives them an opportunity to exact revenge on a person that has wronged them. Offering his clients an attaché case containing proof of the deed and a gun, he guarantees his "clients" full immunity for all of their actions, including murder. In these opening chapters, Dizzy Cordova, a Latina gangbanger who has just finished a prison sentence, is given the chance to avenge her family's murders, and a downtrodden bartender receives the opportunity to exact revenge against the woman that ruined his life.
(Collects Vertigo Winter's Edge #3, 100 Bullets #1-5)