A specialist garda unit is to take a fresh look into the disappearance of six-year-old Mary Boyle, who was last seen almost 40 years ago in Co Donegal.

The Serious Crime Review team will scrutinise the case from when Mary was first reported missing in March 1977.

If anything new is uncovered or warrants further investigation it will be followed up.

Mary Boyle was last seen by her uncle close to her grandparents' house in Cashelard near Ballyshannon.

Mary's twin sister Ann Doherty has been campaigning in recent years for the case to be reopened and has met politicians in Leinster House, the European Parliament, the US and Brussels.