The singer Margo O'Donnell has said she believes the truth about what happened to missing Mary Boyle will be discovered if gardaí arrest the man she believes was behind the schoolgirl's disappearance.
The six-year-old disappeared from her grandparents' farm at Cashelard, outside Ballyshannon, in March 1977.
Ms O'Donnell, a cousin of Mary's late father, Charles, said she believed a YouTube documentary about the case, which was blocked for a time on Tuesday but has become available again, has created a new spark in the investigation.
The Garda’s Serious Crime Review Team is to examine the case.
“I honestly believe that if this person is questioned, then the truth will come out. He has never been arrested in connection with Mary’s disappearance,” Ms O’Donnell said.
The YouTube documentary, Mary Boyle: The Untold Story, was produced by journalist Gemma O'Doherty. It includes two interviews with retired gardaí, who claimed a politician had interfered with the Garda investigation.
Ms O’Donnell said she had approached the politician at the time of the disappearance.
“I went up to him and I put it to him that he prevented the arrest of this man. He denied it, said it was untrue and called me a bare-faced liar,” she said.