A Guatemala judge on Tuesday issued an arrest warrant for the country’s former attorney general and current presidential candidate, Thelma Aldana, on charges of embezzlement, lying and tax fraud.

The warrant for Aldana’s arrest, issued by Judge Victor Cruz, “relates to a corruption inquiry involving illegal hiring,” said a Supreme Court official. Aldana has denied any wrongdoing and planned to return to Guatemala on Thursday.

Aldana has worked closely with International Commission Against Impunity in Guatemala (CICIG), a UN-backed anti-corruption commission, to try to impeach President Jimmy Morales. The mandate of the CICIG has helped prosecutors bring cases against dozens of senior officials and executives. Morales initially supported the CICIG when he was elected three years ago until Aldana and CICIG were trying to impeach him in a campaign financing investigation.

Aldana’s presidential candidacy had granted her immunity and that she would not take action against the arrest order. “We’re not going to do anything. … They know that I’m going to keep up the fight against corruption, and lots of people in Guatemala are trembling because of that,” said Aldana.