Buenos Aires (AFP) - In a Christmas gift gone awry, a woman thought to be the lost granddaughter of an activist who searches for babies stolen during Argentina's 1976-1983 military dictatorship turned out to be someone else.
Two genetic tests showed that the 39 year-old woman in question is not the granddaughter of Maria "Chicha" Mariani, the government said Friday.
Mariani, 92 and nearly blind, is one of the best-known Argentine rights activists, and the Christmas Eve news that she had finally found her granddaughter was the feel-good story of the season. President Mauricio Macri even congratulated her on Twitter.
She is one of the founders of the Grandmothers of the Plaza del Mayo, a human rights group seeking to find children stolen or illegally adopted during Argentina's so-called "Dirty War."
Babies born in captivity to political prisoners or orphaned by assassinations were given to families sympathetic to the regime or even taken in by their parents' killers.
Mariani's granddaughter, Clara Anahi Mariani, was abducted as a three-month-old infant when regime agents killed her mother.
On Christmas Eve a statement from the Anahi Foundation, which Mariani created in 1989 after stepping down as president of the Grandmothers group, said DNA testing had confirmed "with 99.9 percent" certainty that the woman identified as Clara Anahi was Mariani's granddaughter.
That DNA test was carried out privately by the woman, who has not been named.
However two DNA tests -- one in early 2015 and the other made public Friday -- show no relationship between the two women, said Pablo Parenti, head of the government office that searches for children kidnapped during the dictatorship.
The second test was carried out by the National Genetic Data Bank (BNDG), the institution that provides official results for such cases.
"Both reports are conclusive in showing that there is no relationship between the genetic profile of this young woman and the Chicha Mariani family group, nor with the other families that are still looking for abducted children," read the statement.
Mariani urged "caution" in a separate statement, saying that the results of the second test needed to be confirmed.
Mariani will hold a press conference on Saturday to explain what happened, her biographer Juan Martin Ramos Padilla said in a statement.
-- Heartfelt letters --
An estimated 500 babies were stolen by Argentina's military regime, which abducted, tortured and killed opponents and suspected sympathizers.
About 30,000 people were killed or "disappeared" during the dictatorship.
In 2012, former dictators Jorge Videla, who has since died, and Reynaldo Bignone were sentenced to 50 years and 15 years in prison respectively over the regime's theft of babies.
The case of Clara Anahi drew international attention through a series of heartfelt open letters that Mariani wrote to her.
"They tried to convince me that you were killed along with your mother, but I knew you were alive," she wrote in a letter in March.
"My dream, at 91 years old, is to hug you and recognize myself in your eyes.... The greatest wish that keeps me going is for us to find each other at last."
A police officer abducted Clara Anahi on November 24, 1976, when regime agents killed her mother, Diana Teruggi de Mariani, in a raid on their home in La Plata, 60 kilometers (35 miles) outside the capital Buenos Aires.
Diana was a member of the Montonero guerrillas that opposed the regime. She was killed alongside three other members in the raid.
Her husband, Daniel Mariani, was absent that night, but was killed eight months later.
The Anahi Foundation bought the house in 1998 to open a museum dedicated to chronicling the regime's abuses.