[3] Among them was María Ponce, along with the other founders of the Mothers of the Plaza de Mayo, Azucena Villaflor and Esther Ballestrino, and French nuns Alice Domon and Léonie Duquet.

Ponce and most of the group were kidnapped on December 8 in the Santa Cruz Church [es], located in the neighborhood of San Cristóbal of Buenos Aires, where they used to meet.

Probably on 17 or 18 December 1977, Ponce and the rest of the group were transferred to the military airport at the southern end of the Aeroparque from the city of Buenos Aires, where they were sedated and boarded onto a Navy plane, and then thrown while alive into the sea off the coast of Santa Teresita, dying upon contact with the water.

In light of the National Commission on the Disappearance of Persons (CONADEP) investigation and the Trial of the Juntas in 1984, excavations were made in the General Lavalle cemetery, which revealed a large number of skeletal remains from the corpses on the beaches of San Bernardo and La Lucila del Mar.

On July 24, 2005, 28 years after being murdered, based on identification through forensic examination, María Ponce de Bianco was buried in the garden of the Santa Cruz Church [es] in Buenos Aires next to Esther Ballestrino, one of the three mothers kidnapped with her.