China's foreign ministry has removed all references to the detained artist Ai Weiwei from an official transcript of a government news conference.
Eight questions raised by journalists concerning Mr Ai - a fierce critic of the government - were omitted.
Mr Ai was detained at Beijing airport on Sunday. Officials have said he is under investigation for suspected "economic crimes".
Mr Ai's sister told the BBC that police had raided his workshop again.
The artists is a vocal critic of the Beijing government, complaining about a lack of basic freedoms and often incorporating these political themes into his work.
There had been no word on his detention until the Chinese authorities broke their silence on Thursday, saying Mr Ai was under investigation "on suspicion of economic crimes".
Eight out of 18 questions asked at the news conference on Thursday had been left off a transcript posted on the foreign ministry's website on Friday, Hong Kong broadcaster RTHK reported.
There was no explanation by the foreign ministry.
Meanwhile, Mr Ai's sister, Gao Ge, said his workshop in Beijing had been raided for a second time by police "this time targeting the finance office".
She also expressed her concern for her brother's health.
"It's been so many days, more than 150 hours has gone, and he has so many illnesses... We know nothing about his condition," Ms Gao told the BBC's Chinese service.
A number of governments, including the US, Britain and Germany, have raised concerns about Mr Ai's detention.
But China's foreign ministry on Thursday insisted the case had "nothing to do with human rights or freedom of expression".
In the last couple of months, dozens of activists have been taken into custody or house arrest, none of them as open in their criticism as Mr Ai.