The senator in question, Piedad Córdoba, has played a key role in Colombia's peace movement since joining the Senate in 1994 and her mediation efforts have led to the release of dozens of Farc hostages. Her actions have earned her praise from around the world and she was nominated for the Nobel Peace Prize in 2009.
However, as an outspoken critic of the government and the military and a close ally of Venezuelan President Hugo Chávez, her role as a negotiator with Farc rebels has also made her a deeply controversial figure and strongly divided Colombian society. Last Monday she was ousted from the senate for what Inspector General Alejandro Ordóñez described as having gone "beyond the call of duty". According to Ordóñez, Córdoba has "exceeded her functions as well as the authorisation she was given by the government to negotiate a humanitarian exchange."
According to Ordóñez's statement, her dismissal stems from evidence found in computer files captured during a cross-border military raid on an Ecuadorean rebel camp in March 2008. The raid saw senior Farc leader Raul Reyes killed and a number of laptops seized. The files allegedly identify Córdoba under several aliases such as "Teodora de Bolivar", "La Negra" and "La Negrita" and have been reportedly corroborated by various other sources, including legal phone taps. She has been accused of overstepping her role "in favour of other governments" - a clear reference to Venezuela and Ecuador which have both been known to harbour Farc rebels in the past.
A staunch advocate for human rights and the rights of the poor, many have accused her of Farc leanings due to the group's traditional grassroots membership and tendency to attract marginalised members of society. Lidia Solano, a spokesperson for Colombian NGO Justice and Life, described the allegations against Córdoba as "an attack against those who try and protect human rights, an attack against critics of President Álvaro Uribe and ultimately unlawful."
This is not the first time, however, that Córdoba has been accused of colluding with Farc and indeed the very same evidence from the 2008 raid has been used against before. In fact, these computer files were a key catalyst to the ongoing "parapolitics" scandal in which she, alongside over 30 other politicians, which include a number of former President Álvaro Uribe's close allies, have all been accused of links to right-wing paramilitary groups.
Córdoba's ousting also comes during a dramatic few weeks for Colombian politics. Farc's ascendancy was shattered when its top military chief Mono Jojoy (also known as Jorge Briceño and Víctor Julio Suárez) was killed in a large-scale military air strike in Macarena, a Farc stronghold in the south of the country.
Following weeks of increased violence and the death of some 40 soldiers and policemen since President Juan Manuel Santos took office on 7 August, this was a rather unexpected culmination to their latest campaign. Hailed as a triumph for the new president and a disaster for FARC, many doubts have been cast over Farc's future and the rebels' ability to find an adequate replacement for Mono Jojoy. However, in a move to surely reaffirm their status, it was announced that Pastor Alape, a rebel accused of coordinating cocaine operations across central Colombia, would take over his role.
Asides from the evidence from the 2008 raid, it is yet unknown what precipitated both Córdoba's ousting and the re-investigation of two other politicians, Senator Gloria Inés Ramírez and Congressman Wilson Borja. All three have been embroiled in the "parapolitics" scandal since 2008. It is possible that the laptops seized in the latest raid may have revealed more evidence against them, but nothing has been confirmed yet.
Despite being the victim of kidnappings, death threats and several assassination attempts throughout her career, Córdoba has always resolved to continue on regardless of the lack of local support for her work. Yet although she will be contesting the ban, this has undoubtedly been the clearest message yet from the government that she is unwelcome in Colombia.