Bulgarian authorities on Thursday questioned a couple thought to be the parents of Maria, a mysterious blonde girl whose discovery in a Greek Roma camp has made global headlines.
The woman, Sasha Ruseva, was quoted as saying that desperate poverty had forced her to leave behind a baby in Greece and that Maria looked like she might be hers.
"There is a resemblance, but how should I know if she is mine or not?" the thin, dark-complexioned Ruseva told reporters, clutching a small, freckled and pale-skinned child of two or three with dyed red hair.
"I don't know if she is mine or not mine," she said outside the police station in the town of Gurkovo in central Bulgaria, saying she had "not eaten and am sick" since seeing television images of the green-eyed Maria.
She said that she had given her child, reported to have been born in Greece several years ago, to another woman when the girl was aged around seven months, but denied any money changed hands.
She said she would take her back if DNA tests confirmed that she was indeed her mother.
Prosecutors said only that a woman with the initials S.Zh.R. was being investigated for allegedly selling her child in Greece in 2009, and that it had ordered a DNA analysis.
"The investigation was opened after an inquiry conducted in relation to a female child named Maria found in Greece," a statement said.
According to reports in Bulgaria, Ruseva and her husband Atanas Rusev from the town of Nikolaevo have between eight and 10 children, five of whom are blonde and even closely resemble the girl found last week.
Greek news portal Zougla said Ruseva gave birth to a girl on January 31, 2009 in the town of Lamia in central Greece, about 150 kilometres (95 miles) from the camp where Maria was discovered last Wednesday.
However, dental checks on Maria indicate an age of five or six, according to the Greek charity entrusted with her care and since inundated by hundreds of calls from parents of missing children around the world.
Lamia Mayor George Kotronias told Zougla that Ruseva unsuccessfully tried to register her daughter by falsely claiming she was unmarried, and that her application had been rejected.
Police in Greece, who have launched a global appeal via Interpol to find Maria's parents, declined to comment.
The Greek Roma couple looking after Maria, a 39-year-old man and his 40-year-old wife, were detained but say that the child's Roma mother gave them the child because she could not afford to look after her.
The case led to two blonde children aged seven and two being removed from their Roma families in Ireland before being given back after DNA tests, sparking alarm about racial profiling.
The head of the Roma Rights Centre (ERRC), Dezideriu Gergely, told AFP on Thursday that the cases had encouraged stereotypes such as "Roma communities steal babies".
Many Roma communities in Europe do not have dark skin, have blue or green eyes, or are of mixed race, he said.
"Creating the perception that ethnicity can be linked to criminality is discriminatory. The effects of this not only fuel racist stereotypes but are potentially disastrous," rights group Amnesty International said.
Up to 12 million Roma are estimated to live in Europe, according to the Council of Europe, many in extreme poverty with little or no access to jobs, education or health care.