With her blonde hair, scruffy pigtails, green eyes and muddy hands, the young girl stares blankly at the camera in images that have caught the world's attention.
Known as Maria, and dubbed the "blonde angel" , the four-year-old was spotted peeking out from under a blanket at a Roma settlement near the town of Farsala during a police sweep for suspected drug trafficking.
She speaks just a few words in the Roma dialect and Greek, and police think she may be of northern or eastern European origin, possibly from Scandinavia or Bulgaria.
Police have sent Interpol a file with all the evidence they have on the girl, including DNA samples, to seek a possible match with its records on missing children.
They have also contacted international groups and charities that deal with lost or abducted children.
DNA testing has shown the child is not related to the couple, who claim her. They have been arrested and their lawyer has said the girl's mother gave her up at birth.
"We're talking about a woman who could not raise this child and who gave it to the couple in 2009 through a third party shortly after her birth," lawyer Marietta Palavra, said.
"There has been no kidnapping, no robbery, no trafficking," added her colleague Konstantinos Katsavos, who also represents the woman, 40, and her husband, 39. "They did not buy the child."
Greek police want to question the biological mother.
Lawyers hope that relatives of the girl will be found before the couple is questioned by a judge in the central city of Larissa today and possibly charged for "abducting a minor".
Police said the couple had repeatedly changed their version of how the girl, who underwent medical exams at a hospital this weekend, came to live with them.
Media reports say the couple claimed they found the girl abandoned outside a supermarket, and then in another version said they had obtained the child from her Bulgarian mother.
The girl is expected to stay with The Smile of a Child charity.
Additional reporting by Reuters