Colombian conflict dialogue, but President Barco sent an ultimatum to the guerrillas and demanded that they immediately disarm or face military retaliation. Regional guerrilla and Army skirmishes created a situation where each violation of the ceasefire rendered it null in each location, until it was rendered practically nonexistent. By 1990, at least 2,500 members of the FARC-founded Patriotic Union had been murdered, according to historian Daniel Pecáut, leading up to that year's assassination of presidential candidate Bernardo Jaramillo Ossa. The Colombian government initially blamed drug lord Pablo Escobar for the murder but journalist Steven Dudley argues that many in the UP pointed
Pablo Escobar cooperation in high-profile criminal cases. On July 24, a video in which Vallejo had accused Santofimio of instigating Escobar to eliminate presidential candidate Galán was aired by RCN Television of Colombia. The video was seen by 14 million people, and was instrumental for the reopened case of Galán’s assassination. On August 31, 2011 Santofimio was sentenced to 24 years in prison for his role in the crime. Among Escobar's biographers, only Vallejo has given a detailed explanation of his role in the 1985 Palace of Justice siege. The journalist stated that Escobar had financed the operation, which was committed by