Olano pled guilty to charges of bribery to get a reduction in the length of his sentence.
However, the investigation into Olano’s alleged corrupt contracting will continue as he continues to deny the charges.
Earlier in the day Olano testified that Manuel Nule of the Nule Group, the business at the centre of the scandal, paid Senator Ivan Moreno over $2 million in bribes to obtain public works contracts.
Olano has been in jail since last May, when he returned to Colombia to face the charges against him. He was the second person to be incarcerated after Senator Moreno.
The ex-congressman became embroiled in the scandal after newspaper El Tiempo obtained a recording of him discussing the situation with Miguel Nule.