GUATEMALA CITY (Reuters) - Guatemalan police arrested former presidential candidate Sandra Torres at her home on Monday on charges of violating campaign finance rules, just hours before the departure of a U.N. anti-corruption commission that shook the political class.

Sandra Torres, former first lady and presidential candidate of the National Unity of Hope (UNE) political party, attends a hearing in Guatemala City, Guatemala September 2, 2019. REUTERS/Luis Echeverria

A former first lady, the 63-year-old Torres finished second to President-elect Alejandro Giammattei last month in her third attempt to win the office.

For more than a decade one of the Central American country’s most prominent politicians, she has long faced accusations of corruption, allegations she has denied.

The fight against corruption has dominated Guatemala’s political scene since the International Commission against Impunity in Guatemala, CICIG, helped topple a president in 2015.

Torres’ arrest and a case against a sitting minister last week appear to be final blows by the body. Its mandate ends on Tuesday, after 12 years, after being terminated by former President Jimmy Morales.

Without the CICIG, widely viewed as one of the most successful anti-corruption bodies in Latin American history, judges have said they fear it would be difficult to proceed with cases.

Torres was detained by several police officers at her house a few miles outside Guatemala City, her face mostly covered by a headscarf and large dark glasses.

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She was taken to a courthouse in the city to appear before judge Claudette Dominguez, who ordered Torres to placed in custody to await trial.

“She is charged with the crimes of failing to register election financing, and unlawful association,” the attorney general’s office said in a statement. The office said the warrant against Torres was issued on Friday.

Torres has denied the accusations.

“We reject this disproportionate and unnecessary measure against Sandra Torres,” said one of her closest aides, lawmaker Orlando Blanco, on Twitter.

Her center-left National Unity of Hope (UNE) party called her arrest politically motivated, saying in a statement that she had recently offered to cooperate in the case.

At the court house, Torres said she felt unwell and was afraid she would faint. She was allowed to sit in an office to catch her breath.

The charges she faces stem from a case by the CICIG. According to the attorney general’s office, UNE received some $3.5 million in undeclared financing during the 2015 presidential election.

UNE holds the largest number of seats in the new Congress.

Responding to the arrest, Giammattei, who has previously said he would like to see Torres behind bars, said the news put a smile on his face.

“I’m happy that the attorney general’s office is fulfilling its duty, in this and all the cases that have to do with corruption,” he told reporters.