(CNN) -- The charity taking care of a blonde, blue-eyed girl taken by police from a Roma community in Greece has received 8,000 calls from around the world since it issued a call for help in finding her parents.
"At least eight calls have some information that can be used by the police for further investigation," Smile of the Child spokesman Panagiotis Pardalis said Sunday. "Four of these calls are from the United States."
The group is working with Greek authorities, Interpol and Europol to solve the mystery of Maria, the name by which the couple posing as her parents called the 4-year-old.
"This Roma family had 14 children in total, and they were registered with fake birth certificates, so now the police are trying to see whether these children also belong to this family or if there is something else behind this," Pardalis said.
The girl was immediately taken from the couple and entrusted to the care of the Smile of the Child, which will keep her in one of its group homes until her family is found.
"The girl is at peace," Pardalis said. "She is doing much better."
A prosecutor became suspicious when he saw the child with very pale skin in a community of Roma, also known as gypsies, near the town of Larissa in central Greece, Pardalis said.
"It was bad living conditions, poor hygiene. The girl was found in a state of neglect, both physically and psychologically," he said. "We don't have any other information, if this girl was forced to work or to beg on streets."
When the couple was questioned, "they changed repeatedly their story about how they got the child," a police statement said, compounding the officers' suspicions.
DNA testing then "showed that there was not any genetic compatibility" between the girl and the 39-year-old man and the 40-year-old woman, the police said, meaning they cannot be her biological parents.
The two people posing as her parents have been arrested and face charges of abducting a minor, as well as counts of falsifying identity documents, said the state-owned Athens-Macedonian News Agency.
Among the suspect documents found by police was a 2009 birth and baptism registration from Athens authorities, the news agency said.
The woman also had two different valid identification documents and, based on family registration records, appears to have given birth to three children between June and November 1993 and another three children between October 1994 and February 1995, it said.
In fact, the state-run AMNA news agency reported, she had two family residence registrations indicating that she was mother to 10 children: five girls and a boy in Larissa, plus four girls in Trikala.
The man is registered as the father of four more children.
Greece's government has promised to help the child. In the meantime, the little girl is being given support by a police psychologist, the police said.
Anyone with information is asked to call the European Hotline for Missing Children or contact the Smile of the Child.
The girl's discovery will probably prompt speculation that she may have been abducted or trafficked, which, if proved, could serve to fuel prejudice against the Roma community within Greece and elsewhere.
Rights group Amnesty International has called on the European Union to take action to end discrimination against the 6 million Roma, describing them as "the largest and most disadvantaged minority in the region."
In May, Amnesty International said Greece had been found guilty of discrimination against Roma schoolchildren in three rulings by the European Court of Human Rights.
CNN's Laura Smith-Spark and Joseph Netto and journalist Elinda Labropoulou contributed to this report.