Buenos Aires: A 92-year-old activist in Argentina who has spent decades searching for a granddaughter abducted during the country’s 1976-1983 military dictatorship plans to resume her search — after being misinformed the woman had been found.

Maria “Chicha” Mariani was one of the founders of the Grandmothers of the Plaza de Mayo group, which fought to find children stolen or illegally adopted during Argentina’s so-called “Dirty War.”

Mariani is one of the country’s best known rights activists, and the Christmas Eve news that she had finally found her granddaughter — who was abducted as an infant when regime agents killed her mother — was the feel-good story of the season.

President Mauricio Macri even congratulated her on Twitter.

But then on Friday, the government said two genetic tests showed that the 39-year-old woman in question was not Mariani’s granddaughter after all.

Mariani, who is nearly blind, “is extremely sad and in pain,” spokesman Juan Martin Padilla said Saturday.

Apparently “she let herself get swept up in the emotion when someone came up to her with a test result that showed positive,” he added.

That DNA test was carried out privately by the younger woman, who has not been named.

Despite the crippling disappointment, Mariani hasn’t given up, Padilla said.

“We are going to keep working as we always have, to see justice done, the truth told, and no one forgotten,” Padilla told reporters outside Mariani’s home.

An estimated 500 babies were stolen by Argentina’s military regime, which abducted, tortured and killed opponents and suspected sympathisers.

Some 30,000 people were killed or “disappeared” during the dictatorship.