Cerrajo

Cerrajo is a prison boss in the game Gangstar: West Coast Hustle. Pedro and Juan meet him and join his gang while in prison, during a flashback episode. After they broke out of prison with Cerrajo and his gang, he is never met again.

We later learn that they tried to hijack a bank heist together in Tijuana, which failed, explaining why Pedro and Juan left Mexico for L.A.