Colombia's Rebels Catch the Gold Bug

Under a bright sun in northern Colombia this past April, heavily armed police raided a clandestine gold mining operation equipped with new excavators and other machinery. The police rounded up half a dozen workers at the site for questioning. The real quarry, however, was not there—the guerrillas and gangs who took a cut of the gold in return for letting mining equipment operate on their turf.

Colombian President Juan Manuel Santos has ordered more raids because gold has become a source of funds for the criminal groups that once relied solely on the cocaine trade. Criminals and rebels enriched by gold can recruit and arm men more easily, threatening to erode hard-won gains in security over the last decade, says Daniel Mejía, an associate professor of economics at University of the Andes in Bogota.