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 as well as being rumored to reach as far as Asia. It is alleged that Escobar backed the 1985 storming of the Colombian Supreme Court by left-wing guerrillas from the 19th of April Movement, also known as M-19. The siege, a retaliation motivated by the Supreme Court studying the constitutionality of Colombia's extradition treaty with the U.S., resulted in the murders of half the judges on the court. M-19 were paid to break into the Palace and burn all papers and files on "Los Extraditables", a group of cocaine smugglers who were under threat of being extradited to the U.S.