QUITO, Ecuador (AP) — An Ecuadorian presidential candidate known for speaking up against cartels and corruption was shot and killed Wednesday at a political rally in the capital, amid a startling wave of gang-driven violence in the South American country. President Guillermo Lasso confirmed the assassination of Fernando Villavicencio and suggested organized crime was behind his slaying, less than two weeks before the Aug. 20 presidential election. Villavicencio was one of eight candidates, though not the front-runner. Ecuador’s attorney general’s office said that one suspect died in custody from wounds sustained in a firefight after the killing, and police detained six suspects following raids in Quito.