BOGOTA, July 28 (Xinhua) -- The president of Colombia's Senate confirmed on Saturday that ex-president Alvaro Uribe has resigned from his Senate seat after the Supreme Court of Justice opened a criminal investigation against him.
Senate President Ernesto Macias said in a post on Twitter that he had received Uribe's resignation letter.
"We have asked him to reconsider his decision," Macias said.
Uribe, who served as a two-term president of the South American country from 2002 to 2010, is the political mentor of President-elect Ivan Duque. He is currently being investigated on several charges, including obstructing justice, witness tampering and murder.
In a Twitter post earlier this week, Uribe said he was quitting Senate because "I feel morally impeded to be senator" following the allegations.
"I will hand in my resignation so my defense does not interfere with the tasks of the Senate," he said.
The investigation was opened after Uribe accused leftist Senator Ivan Cepeda of witness tampering while the latter was researching Uribe's connections to paramilitary groups for a book.
Media reports said while investigating that claim, the court found that witnesses had been threatened and possibly killed by Uribe's associates.
In a statement, the court said that "apparently with his consent, people with ties to ex-president Uribe ... manipulated witnesses."
The court found "evidence" to begin the investigation on Uribe, the statement added.
