A US boy kidnapped from a public park aged 6 has been reunited with his family after a DNA test unravelled a mystery that had tortured his loved ones for more than 70 years.

Six-year-old Luis Albino, one of five children who moved from Puerto Rico to San Francisco with their mother Antonia, was playing with his 10-year-old brother Roger on February 21, 1951, in San Francisco’s Jefferson Square Park when he was approached by a woman who spoke to him in Spanish.

The woman, in her 30s with a green bandana over her hair, promised to buy the little boy lollies if she went with him and he followed along.

Roger followed them for a while before heading home to tell an adult.

But they were gone.

Family immediately called police and officers commenced a search, initially not believing Roger’s story and raising the theory that little Luis had wandered off and into the nearby bay.

But Roger never changed his story and Antonia never stopped believing her little boy was out there somewhere.

A 15-year review of the case published in 1966 by the Oakland Tribune gave heartbreaking details of the desperate mum’s visits to the police station for fresh information on her son.

“She came once a week, then once a month, then at least once a year, to see the shake of the head, to have the answer ‘no’ translated for her although she could read it in the officers’ faces,” the Tribune wrote.

Oakland police’s Dominic DiFraia told the newspaper that Antonia Albino had been through the “tortures of the damned”.

1966 was the year that Luis Albino turned 21 and his family launched into a new phase of their search, hoping that he might appear on official records as he entered adulthood.

They even travelled back to Puerto Rico, where they thought he might have been taken.

There was no trace.

DNA test ‘just for fun’

Alida Alequin is Luis’ niece, the daughter of his sister, and she said the family never forgot the little boy.

“All this time the family kept thinking of him,” Alequin told the Mercury News.

“I always knew I had an uncle. We spoke of him a lot. My grandmother carried the original article in her wallet, and she always talked about him. A picture of him was always hung at the family home.”

While that hope remained the trail had long gone cold, until a DNA test that Alequin took “just for fun” turned up a match for an uncle – across the country on the east coast of the US.

She reached out to him but did not get a response and further searching offered no further clues.

But Alequin tried again this year, using newspaper clippings to close the loop on a story that had haunted her family for 73 years.

Confirmation came from the FBI and California Department of Justice, who obtained DNA from Luis and Alequin’s mother.

“In my heart I knew it was him,” Alequin said, “and when I got the confirmation, I let out a big ‘YES!’”

Roger Albino, left, with his younger brother Luis after the pair were reunited. Photo / Alida Alequin

In June of this year, Luis came home.

“Thank you for finding me,” he told Alequin.

Now a father and grandfather himself, the retired firefighter and Marine Corps veteran met with family, including his brother Roger who first raised the alarm all those years ago.

“They grabbed each other and had a really tight, long hug. They sat down and just talked,” Alequin said.

Roger died shortly afterward “at peace with himself, knowing that his brother was found”.

Their mother never got to see the boys reunited, dying in 2005 and still believing that Luis was alive.

“She never forgot him,” Alequin said. “She always said he was still alive.

“She had hope she would see him. She never gave up that hope.”