A Christmas miracle? A long-lost granddaughter? DNA tests dash hope in Argentina

This story was supposed to be a happy one for a 92-year-old woman in Argentina.

Chicha Mariani's granddaughter was stolen as a baby nearly four decades ago during Argentina's Dirty War. It's a period that still haunts the country. Some of the children went to Argentine couples who wanted a baby. The parents? They were "disappeared" — put in secret prisons, tortured. Thousands were killed.

On Christmas Eve, a woman showed up at Mariani's doorstep holding a private DNA test that showed a positive match. She said she was Mariani’s long-lost granddaughter.

"Can you imagine, it's Christmas Eve and the news that a grandmother that has been searching for her daughter for 39 years suddenly gets to meet her," says the BBC's Veronica Smink, who is based in Buenos Aires. "Everybody was so thrilled."

Mariani's organization, Abuelas de Plaza de Mayo, wanted to be sure. So the next day they came out with a statement saying they would do their own tests.

They went to the National Genetic Data Bank. "It's the official institution that has to confirm whenever there is an announcement of a match," says Smink.

Many hoped for a Christmas miracle. The story raced across social media in the country.

"It was a huge disappointment when it was announced that there wasn't a match," says Smink.

Many think this was a hoax. That someone wanted to swindle Mariani. But Chicha Mariani is far from a super-wealthy individual. She's just well known.

What’s not known is much about the woman who claimed to be the granddaughter. Reporters are still digging into her past.

The abduction of Mariani's granddaughter was, says Smink, "such an emblematic case of the disappearance."

About 500 children were taken during this time. Smink says that 120 have been reunited, thanks to the efforts of Mariani's organization.

Sminks says Mariani hasn't commented publicly on the story. She did release a statement conveying her sadness and disappointment. 

"But she also made it clear," Smink says, "that she will continue her 39-year search for her granddaughter."