The four Mexicans apparently wanted to be pioneers of sorts. But they were breaking the law in a big way, Nigerian officials say, to achieve that distinction. Nigerian drug agents say they have arrested four Mexicans who were helping to build a methamphetamine "super lab." It is believed to have had the potential to rake in billions of dollars, the nation's National Drug Law Enforcement Agency said Monday. Spokesman Mitchell Ofoyeju said it was the first industrial-scale production of crystal meth found in West Africa, and possibly on the continent. "The Nigerians invited the Mexicans in to leverage their expertise...