The claims have taken on new relevance as Colombians start to come to grips with their violent past and seek a lasting peace with Marxist rebels.
Yesterday's questioning of the conservative leader, who was president in 2002-10, was orchestrated by leftist Senator Ivan Cepeda. Both men have suffered firsthand a half-century of political violence.
Uribe's father was killed in a guerrilla ambush. Cepeda's senator-father was gunned down on a Bogota street in 1994 as part of a campaign of terror against leftist politicians following an earlier peace deal.
"Colombia is at a crossroads between perpetuating war, hate and violence or opening the difficult path to reconciliation and peace," Cepeda told a packed assembly of lawmakers and journalists. "Knowing the truth is key for the political process our country is undergoing."
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But after walking across Plaza Bolivar to present evidence to the Supreme Court accusing Cepeda of slander, Uribe returned to defend his record and attack the current administration.
As president, Uribe beefed up security forces and intensified military offensives against the FARC, helping to dramatically reduce what was then one of the world's highest homicide and kidnapping rates.