BOGOTA, Colombia (AP) — Colombian police arrested the president’s son Saturday as part of a high-profile money laundering probe into funds he allegedly collected from convicted drug traffickers during last year’s presidential campaign.

President Gustavo Petro, a former rebel who rose through Colombia’s political ranks as an anti-corruption crusader, said he wouldn’t interfere with the investigation.

“As an individual and father, it pains me to see so much self destruction and one of my sons going to jail,” Petro said in an early morning message on X, the social media platform formerly known as Twitter. “As president of the republic, I’ve assured the chief prosecutor’s office that it will have all of the guarantees so it can proceed according to the law.”

The arrest of Nicholas Petro is a major blow to the government, which has been buffeted by conservative attacks from day one at the same time it has struggled to maintain bipartisan support for Colombia in the US, a longtime ally in the war on drugs and fight against illegal armed groups.

The investigation stems from shocking declarations made by Nicolas Petro’s ex-wife, Daysuris del Carmen Vasquez, to local media outlet Semana earlier this year.

In the extended interview, Vasquez detailed how she was present at meetings when her husband arranged a donation of more than 600 million pesos (around $150,000) from a politician once convicted in Washington of drug trafficking and who was seeking the Petro campaign’s support to resume his political career.

She said President Petro was unaware of her son’s dealings and the money he collected in his campaign’s name was kept inside a safe inside the couple’s home in the coastal city of Barranquilla.

Nicolas Petro has denied his ex wife’s claims as unfounded.

The chief prosecutor’s office said in a statement that Nicolas Petro and his ex-wife were taken into custody on orders of a court in Bogota around 6 a.m. local time Saturday. It said that once brought before a judge, prosecutors would seek their provisional detention as it investigates the two for money laundering.