BOGOTA - At least 48 people were killed - some burned alive - in a 10-day "orgy of killing" in and around a river port in southern Colombia, a town mayor said yesterday.The mayor said a right-wing death squad was responsible but national police chief, Gen Rosso Jose Serrano, denied the report of the massacre in Puerto Assis, in Putumayo province, saying that Communist agitators were spreading misinformation.