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
Mario Uribe Escobar to the Colombian parapolitics scandal, Uribe-Escobar was first mentioned by Jairo Castillo Peralta aka "Pitirri" who was a former member of the paramilitary group United Self-Defense Forces of Colombia (AUC) and was a personal bodyguard of former politician Álvaro García Romero also implicated in the scandal for mingling with paramilitaries. From his exile in Canada, Castillo-Peralta said that Uribe-Escobar had met with AUC top commanders in northern Colombia to negotiate cheaper land in the region of Caucasia and in the Department of Sucre. Uribe-Escobar responded to this saying that he did not have any land in Caucasia or Sahagún but