Ribera said on Facebook on Saturday that Judge Armando Zeballos extended her mother's preventive detention "without evidence" or "legal criteria".
In August, the Bolivian general prosecutor's office brought charges of genocide against Anez, who was arrested in March, as part of a coup investigation, on suspicion of terrorism, sedition, and conspiracy.
The charges are based on a report by the Inter-American Commission on Human Rights investigating the 2019 crackdown on protests in Bolivia during Anez's tenure. The commission considered the actions of law enforcement officers a massacre, confirming that at least 37 people were killed and hundreds of others were injured, with most of them having been civilians protesting against Anez.
In November 2019, Evo Morales resigned as president and left Bolivia under pressure from the military, after the Bolivian opposition, led by Carlos Mesa, claimed that there were mass violations during the October 2019 vote. Most of Bolivia's senior officials resigned in his wake.
Power in the country was assumed by then opposition vice speaker of the senate, Jeanine Anez. Morales called the events a coup. Anez arranged for a new presidential vote, which took place on 18 October 2020. Luis Arce from Morales's party Movement for Socialism (MAS) won the election.
Anez is still awaiting a trial date. In August, a Bolivian court added another six months to her detention, until March 2022.