The FBI is looking into whether a child found at a gypsy camp in Greece is a missing US girl.
FBI spokeswoman Bridget Patton said the two-year-old disappearance of Lisa Irwin from her Kansas City home remained an open investigation and that agents followed up on all tips.
She said the agency began receiving calls after the image of a girl found with a gypsy couple appeared in media reports. A couple charged with abducting the girl are in custody as an international search for the child's biological parents gathers pace.
A dental examination showed the mystery girl, known only as "Maria", is older than previously thought, five or sixs old instead of four. Lisa Irwin would be three in November.
John Picerno, a lawyer for Lisa's family, told Kansas City media outlets that he had spoken to authorities about the investigation in Greece.
The girl's parents, Deborah Bradley and Jeremy Irwin, have said they believe someone snatched the girl from her cot when she was 10 months old. Mr Irwin said that when he returned home from a late shift on October 4 2011, the front door was open and the baby was missing.
Police and the FBI conducted extensive searches, even sifting through a Kansas landfill site. No one has been charged. There is a 100,000-dollar reward offered to anyone with information.
Police and a private detective are still investigating, but authorities have said the tips and leads have slowed considerably, down to about one a week. During the first year, detectives worked more than 1,600 leads and countless baby sightings.
Ms Bradley and Mr Irwin have repeatedly said they did not harm Lisa and had nothing to do with her disappearance. Ms Bradley has said she and Mr Irwin think someone took Lisa and is raising the child as his or her own.