The drug kingpin Estrada ran a successful drug cartel that was becoming too influential in Miami. Officer Harry Morgan of the Miami Metro Police Department began to investigate the cartel, implanting a CI by the name of Laura Moser to infiltrate the organization. She succeeded, however Estrada was tipped off by an underling of her contact with Harry, thus his anger took control and he ordered Welsh as well as Lipsey and Santos Jimenez to take care of this problem.
The three of them captured Laura as well as her sons Dexter and Brian Moser with the addition of several other people. They brought all of them to a shipping container located in the Shipping Yard and Santos used a chainsaw to kill everyone except the two children. Harry would later discover Dexter amongst the carnage three days later, bringing him home for adoption while Brian went to a psychiatric hospital for care.
While Estrada's fate is unclear, Santos was let off due to a lack of evidence surrounding his name. Welsh was killed off in a drug deal gone bad, and as for Lipsey, he's currently serving a life sentence without the possibility of parole.