The child was found during a drugs and weapons raid on a travellers’ camp in central Greece last week.
Police noticed the lack of resemblance between the blond, blue-eyed child and her parents, and found further discrepancies when they investigated the family’s documents.
“We never abducted this child we just adopted her”
The couple have admitted the child is not biologically related to them, a claim backed up by DNA tests, however insist that she was given to them legitimately.
Maria is currently being cared for by Athens-based charity The Smile of the Child, which has already received over 8000 calls in response to an appeal for information about the girl.
A 40-year-old woman and a 39-year-old man are due to appear in court this afternoon, accused of abducting a minor and holding false papers.
However the Roma community have hit back at the accusations, claiming the couple looked after Maria well, with the head of the Roma association saying that the pair treated her better than their biological children and that she loved them.
But the couple is also suspected by social workers of involving the girl in a sex ring and sending her out to beg.
The couple’s lawyer, Kostas Katsovas, said they were currently carrying out a search for the girl’s mother to back up their claims.
‘Our clients' claim is that “we never abducted this child we just adopted her” in a way that was not legal, that we can confess, said Mr Katsavos.
'Kate and Gerry McCann "The case has given us great hope"'
Greek authorities say the couple was holding false papers, claiming the woman had given birth to six children within a 10-month period.
The case has reportedly brought fresh hope to two families in the UK with long-missing children.
Two-year-old Ben Needham disappeared while on a family holiday on the Greek island of Kos in 1991. His sister said the discovery of the blonde-haired girl in central Greece gave them "great hope".
Kate and Gerry McCann, whose three-year-old daughter Madeleine went missing in Portugal in 2007, said the case also gave them hope that she would one day be found alive.