"The pain is immense. Her bravery in confronting State terrorism will remain with us. She turned her tragedy into a collective fight for justice," the organization tweeted.
During the 1970s, the Argentine military dictatorship kidnapped two sons of Vallino. In June 1977, Monica, her youngest daughter, was kidnapped when she was eight months pregnant. She gave birth to a girl, Maria Jose, while she was in captivity at the clandestine center "Pozo de Banfield".
On August 5, 1977, Vallino's only son, Mario Lemos, was kidnapped from his job. Days later, police forces raided the house where the eldest daughter Maria del Consuelo lived. However, they couldn't find her because she was already out of the country.
Vallino and her husband searched for their children. That's when they heard about the mothers that were meeting in the Plaza de Mayo to demand the return of their kidnapped family members. She joined the group.
Thanks to the support of the Mothers and Grandmother of Plaza de Mayo, Haydee located the whereabouts of her granddaughter, Maria Jose. After the baby was born in captivity, a policewoman took her and registered the child as her own.
After a genetic analysis was made in October 1987, Maria Jose, 10, was returned to her grandparents. She was the 38th missing granddaughter that the Plaza de Mayo organization was able to recover.
"I could find Maria Jose thanks to the Grandmothers. I couldn't have done it alone. Every day I am grateful to have been part of this group," the founder said frequently.
Vallino was one of the first 12 women who remained struggling for 43 years to find their loved ones. They sacrificed their lives in the search of memory, truth, and justice.