Liber Andrade is a passenger in a car that nearly collides with another car. The driver of the other car gets out and screams at Andrade, and Andrade gets out of the car and starts to fight with him. At which point the guy pulls a knife and cuts Andrade in the neck. When the fight ends, the adversaries and bystanders generally dissipate. In the meantime, Andrade walks to his nearby apartment, grabs a shotgun, and returns to the scene of the fight. He aims the shotgun at a couple of guys at the scene, who scream "We're not in it, we're not in it!" But Andrade doesn't believe them, and fires three shots, killing one of the victims and injuring the other.
Turns out that the victims were right. They were just bystanders, one of whom just happened to be dressed similarly to the guy who cut Andrade in the fight. So Andrade blew away a dude who never even touched him. And will spend 15 to life in prison -- and, thereafter, be promptly deported to Mexico -- as a result.
Yet another reason not to shoot a guy with a shotgun.