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
Loving Pablo, Hating Escobar a political scandal in Latin America and the Hispanic television channels in the US, due to Vallejo's description of the relationship of Pablo Escobar and the Medellin and Cali cartels with several presidents - like Alvaro Uribe, Alfonso López and Ernesto Samper - and Colombian enforcement agencies. Thanks to Vallejo's revelations, the Colombian government reopened the so-called "cases of the century": the siege of the Palace of Justice, followed by a massacre of more than 100 people, including eleven Supreme Court Justices, committed by the army; and the assassination of Luis Carlos Galan in 1989. Vallejo's book was commented by