Mexican Meth Rules

South of the border drug cartels have become the largest suppliers of methamphetamine to the U.S. The Mexican cartels are also ruthlessly brutal.

MEXICO CITY - Four guards lay dead in pools of blood, their hands and feet bound with gray duct tape, as dawn broke over the Medix pharmaceutical plant in Mexico City. The gate was open, the security system dismantled.

It looked as well-planned as a bank heist. Except these robbers made off with a far bigger treasure: more than one ton of the chemical pseudoephedrine, enough to make 4 million hits of crystal methamphetamine, the hottest drug in America. The finished product could fetch $120 million on U.S. street corners.

The robbery at the Medix lab in July is part of a boom in Mexican meth as "superlabs" controlled by Mexican cartels take over what was once a mom-and-pop business in the United States.

The cartels' labs in Mexico and California provide an estimated 80 percent of the meth in the U.S. According to Arizona Attorney General Terry Goddard, the labs are sophisticated, well-armed and well-financed.