Not much is revealed about Sanders, however, it is heavily implied that he is involved in organized crime and corruption with the Vice Department. It is also implied that he has been caught in criminal activities on numerous occasions in the past, only to easily buy his freedom and rig outcomes in court cases.
Sanders' base of operations was held in the abandoned Masangkay Metal Foundry. With Ernesto Juarez in his employment, Sanders headed a large reefer distribution ring stretching across the country. Ernesto performed all of the work and recruited other Mexican immigrants for Sanders, who were given silver dollar coins as a mark for being part of the gang. Most of Sanders' workers never met Sanders in person or knew his true identity, thus he was feared as an elusive and powerful crime lord.
Events of L.A. Noire
While investigating the reefer ring, Detectives Cole Phelps and Roy Earle discovered a link to the Masangkay Metal Foundry through the silver dollar coins. They raided the factory and killed all of Sanders' henchmen in a shootout after which Sanders is arrested. His arrangement with the Vice Department and their corruption becomes evident to Phelps, and it is very likely that Sanders' trial would end in his favor and would be released.