Crime and violence were already on the upswing in Colombia before the 39-year-old presidential candidate Miguel Uribe was shot at a campaign rally in Bogota in June. And 10 days after he died from his wounds on Aug. 11 , two separate criminal groups exploded a car bomb outside the air force base in Cali and downed an army helicopter with a drone; at least 18 people were killed , civilians and army officers. The violence has raised the spectre that after more than two decades of security gains