The case came to notice after Phoebe was admitted to a hospital with serious problems in her kidneys, which doctors said were caused by traumatic injuries, official media here reported today.
Phoebe, who was adopted by the unknown foreigner, is still in critical condition after a third surgery for kidney contusion and intestinal obstruction.
The man reportedly disappeared after Pheobe was taken to the hospital and could not be reached.
An unidentified volunteer taking care of Phoebe said her foster father is an American, and that he once paid visit and left several thousand yuan for her treatment and never showed up again, state-run China Daily online reported.
More From This Section
Another volunteer caring Phoebe said around two years ago, he saw the foreigner with about 10 Asian children, most of them with congenital diseases including cleft lip and mental retardation.
Some volunteers said they have seen the man "pushing, pulling and cursing the kids in public".
A report in the Global Times said Phoebe was beaten by the 50-year-old jobless foreigner. He has claimed to have lived in China for 30 years and speaks fluent Chinese.
Observers said the case reflects the absence of a monitoring system of children's rights which has made some orphans vulnerable to improper or unauthorised adoption.
Foreigners need to apply to adoption agencies approved by both China and their home country if they want to adopt Chinese children, Zhang said.