Colombian rebels kill nine police "The authorities say it was planted by the Farc left-wing rebel group near Landazuri, 160km (100 miles) north of the capital, Bogota. The policemen were taking part in a mission to destroy coca bushes, which supply the raw material for cocaine, a key source of income for the rebels." Internal disintegration An abundance of natural resources (oil, diamonds, opium, coca...) appears to aggravate what Paul Collier has termed the "economics of civil war".