A person who said she was Dai's wife said he was "under investigation" when China Daily called Dai for comment on Sunday.

A staff worker at the bureau of population and family planning in Nan'an, who declined to be identified, confirmed the incident and that punishments had occurred.

"The eight people in the picture were there because their relatives have violated the family planning policy," the anonymous official said.

"Local officials had visited his house many times, but his father always refused to admit to the violation and refused to provide a means of contacting his son."

"That day, the officials may have got annoyed so they took his father away, asking him to tell them how to get in touch with their son," he said, adding that a family planning department "absolutely has no power to put people away".

He said the incident was an isolated case, and that the bureau's inspection teams didn't know of similar incidents in other places.

Contact the writer at wangqingyun@chinadaily.com.cn