BOGOTA Nicolas Petro, the son of Colombia's President Gustavo Petro, will face trial for alleged crimes of illicit enrichment and money laundering while serving as a politician in the province of Atlantico, the attorney general's office said on Monday.

A written indictment against Petro was filed in the Criminal Courts of the Specialized Circuit of Barranquilla, the attorney general's office said in a statement.

Petro was arrested in Barraquilla, the capital of Atlantico, in July alongside his ex-wife, Daysuris del Carmen Vasquez, who is being held on similar charges.

At a hearing in August, Petro pleaded not guilty but said he would collaborate with prosecutors, who accuse him of buying properties valued at $394,000 with money that did not come from his salary.

The deal Petro negotiated with prosecutors could have won him benefits such as reduced sentences and house arrest but the deal fell through after a deadline to deliver information and evidence of the other people involved was missed, according to the attorney general's office.

A judge will be assigned by the courts to oversee the case in due course, the statement said.

According to the charges, Nicolas Petro received money from accused drug traffickers in exchange for including them in the president's peace plans.

The president has denied awareness of any illegal activities and said he will continue with his administration's policy plans.

The scandal threatens to hamper his pursuit of peace or surrender deals with armed groups and an ambitious reform agenda, which was already facing challenges amid the breakdown of the government's prior congressional coalition.

(Reporting by Oliver Griffin and Luis Jaime Acosta; Editing by Michael Perry)