SHIJIAZHUANG, Jan. 2 -- Police in north China's Hebei Province on Thursday opened an investigation into a case involving a baby girl who was abducted by local government 18 years ago, according to local authorities.

The parents of the girl, Liu Laogen and Xia Fengge, reported to local police in Anxin County on Nov. 4 that their third child was taken away by officials from a family planning commission in 1995.

But the case was not immediately filed. Police officers said they had been searching for clues since November but found nothing.

"We have asked related people mentioned by the couple but none provided useful information," said Shao Yongjin, chief of the political section of the Anxin public security bureau. "After all, it was 18 years ago and some of those who could offer clues either retired or passed away."

The couple recalled that their baby girl was taken away when she was only 11 days old because they had violated the family planning policy. They said a man sent from the local public security bureau left them 400 yuan (66 U.S. dollars).

Liu said they had to give up the baby at the time or they would have been beaten up. Several older villagers told Xinhua that they knew of the matter and said that it really happened.

According to China's family planning policy, rural households can have a second child if the first born is a girl, but a third child is not allowed.

"We just want to know where our daughter is, if she is still alive," said the couple.

They submitted an application for state compensation to Quantou township government in October, claiming a total amount of 1,590,840 yuan. But the government turned down their application on the grounds that their accusation was not yet backed by judicial authorities and exceeded the 2-year legal memory.

The couple later sued the county government for failing to disclose government information in December. The government responded it was not their responsibility to obtain, record and save the adoption information, so there was no information for them to disclose to the couple.