Samuel 'Sammy' Alvarez was a former Mexican Jalisco State Police officer and later the right-hand man of drug lord Ernesto 'Don Neto' Fonseca Carrillo.
Alvarez was forced by Don Neto into working for him as punishment, and he decided to stick with his new boss. Alvarez handed out bribes, buying the entire police force of Tijuana to use in the war against Alberto Sicilia Falcon. Alvarez played a minor, but significant part in the abduction of DEA Special Agent Enrique Camarena Salazar. He provided the distraction required to allow DFS operatives to sneak up and abduct Camarena. Later, Alvarez accompanied Don Neto and several associates to a resort town for the drug lord to enjoy a last sensation of hedonism before his eventual arrest for the involvement in Camarena's murder.
Alvarez was the first one to notice police officers sneaking into Don Neto's safehouse. He tries to warn others, but is eventually subdued and arrested. Don Neto is captured, and they both are made to sit the same police car. Alvarez asks his boss about the person responsible for the raid, and Neto thinks he was betrayed by Miguel.