GUATEMALA CITY (Reuters) - Guatemalan President Jimmy Morales will ask United Nations Secretary General Antonio Guterres to remove the head of a U.N.-backed investigative body probing the politician’s family for suspected graft, two government officials said on Wednesday.

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Morales, a former comedian elected on a pledge to fight corruption, has been tarnished by a graft probe focused on an elder brother and one of the president’s sons. It is led by the International Commission Against Impunity in Guatemala (CICIG).

Speaking on condition of anonymity, the officials said Morales would travel this week to New York, where he would ask Guterres to replace CICIG chief Ivan Velasquez, a Colombian whose tenure is scheduled to expire in 2019.

Guatemalan Attorney General Thelma Aldana said on Tuesday that she would resign if the president ousted Velasquez.

Guatemalan presidential spokesman Heinz Heimann told a news conference that Morales would meet Guterres on Friday afternoon and discuss issues including how to improve the CICIG.

Heimann added that Morales aimed to propose a new framework for combating crime during his visit, but declined to say whether he would ask for Velasquez to be removed.

The U.S. embassy in Guatemala said that it “firmly supported” Velasquez’s work at the commission.

“We believe it is crucial that CICIG continue its mission, working with Guatemalan institutions, to strengthen Guatemala’s democracy,” the embassy said.

Stephane Dujarric, Guterres’ spokesman, said the U.N. had not received any complaints about Velasquez from Guatemala’s government and said Guterres “heartily commends the work of commissioner Velasquez,” who is Colombian.

Velasquez and the CICIG led the probe into an alleged multi-million dollar customs racket that resulted in the 2015 arrest and imprisonment of former Guatemalan President Otto Perez, his vice president, Roxana Baldetti, and other top officials.

Perez and Baldetti are currently on trial on a string of corruption charges, including bribery. They deny any wrongdoing.

That scandal sparked public outcry in Guatemala and was instrumental in paving the way for Morales to win the presidency.

However, the fraud probe into Sammy Morales, the president’s brother, and Jose Manuel Morales, the president’s son, has sparked protests and calls for his resignation.

The pair are under investigation over suspicious payments linked to the mother of Jose Manuel Morales’ girlfriend in 2013. The men are under house arrest and deny any wrongdoing.

The CICIG’s investigations in Guatemala had strong backing from the Obama administration.