Colombians have staged protest rallies around the country, demanding the resignation of Attorney General Nestor Humberto Martinez.
Martinez has been accused of not investigating graft cases he was aware of.
He formerly worked as a legal adviser for one of the Colombian partners of the Brazilian construction company Odebrecht which is widely implicated in a far-reaching corruption scandal.
Demonstrators on Friday marched to prosecutors' offices in Bogota, Cali, Barranquilla, Bucaramanga and other cities, broadcaster Caracol reported.
"The behaviour of prosecutor Martinez ... is destroying trust in state institutions," said Pedro Pablo Salaz, one of the organisers of a demonstration in Tunja in the north.
Odebrecht is under investigation by the attorney general's office for allegedly offering bribes in exchange for contracts, as the company has admitted to doing across Latin America.
Suspicions of a cover-up mounted after two key witnesses in the case died in suspicious circumstances.
Three former Odebrecht executives on Friday addressed a Colombian judge via video conference from Brazil, apologising for corruption cases under investigation, according to Caracol and other media.
The apology was one of the conditions on which prosecutors had agreed not to sue them.
Demonstrators said they wanted Martinez to follow the example of Peru's attorney general Pedro Chavarry, who stepped down earlier this month amid allegations that he tried to prevent an investigation into links between Odebrecht and some of the country's politicians.
The Brazilian giant has admitted to paying bribes worth nearly $US800 million ($A1.1b) in 12 countries, 10 of them in Latin America.
Australian Associated Press