After graduating as Economist from the Externado University in Bogotá, 27-year-old Araújo ran for the Chamber of Representatives, representing the Liberal Party and was elected. Two years later, along with his father, he founded a dissident political movement called Alternative for Social Advance. After his second term in the Chamber, he ran for the Senate receiving more than half of his votes from the department of Cesar and Bogotá, where he got the highest vote for someone from the Caribbean Region. His movement supported Álvaro Uribe for the Presidency of Colombia. The voter turnout in the Cesar raised suspicion, because of the influence of paramilitary forces in the area. In May 2005, Semana published an article revealing a possible plan by paramilitary forces to influence elections. The Department of Cesar was divided into two zones, the G-8, formed by 8 municipalities in central Cesar Department where revenues from mining industry are high, and in which Senator Mauricio Pimiento and Representative Jorge Enrique Ramírez got most of their votes, and the G-11, formed mostly by southern municipalities where Representative Miguel Duran Gelvis and Senator Araújo had a high turnout. Araújo responded to these accusations by citing years of hard work politics and his family's influence in the region. He also pointed out that results, like the ones in Tamalameque where he received more than 70% of the total votes, were easily explained because of the influence of his third runner-up, Ricardo Chajín Florián, who had been Mayor of Tamalameque. In the Senate, Araújo was a member of the Fifth Commission of the Senate in which he promoted Hydrocarbon projects and proposed the Mines Code which is cited for duplicating the production of coal in Colombia. He was also a proponent of equal ownership rights for gay couples, and integrating demobilized members of the Cacique Nutibara Bloc into the Armed Forces of Colombia if they met certain judicial requisites. He was temporarily replaced in the Senate from 17 August 2004 to 17 February 2005 by Ricardo Chajín Florián, the third-runner up in his list.
Parapolitica scandal
On January 19, 2006 Araújo was first accused by then candidate for Senate Gustavo Petro, of having ties with paramilitary groups headed by the now demobilized paramilitary leader Jorge 40 and his men. The Supreme Court of Colombia investigated the accusations in what became known as the Parapolitics scandal, as a result, on 16 February 2007, Araújo was arrested along with other senators for having ties to illegal paramilitary groups.
Arising from his investigation in parapolitics, Araújo was also formally accused of the kidnapping and extortion of former Mayor of Valledupar, Elías Ochoa Daza's brother Víctor. He was found guilty of the charges and sentenced to 9 years and 3 months of prison on March 18, 2010.
