A Chongqing police spokesperson who gave his/her name only as Deng declined to comment on Tuesday, saying only that authorities have the right to seek evidence from Zhu.

Si Weijiang, an attorney for DeBund Law Offices in Shanghai, said police can only ask for the sex tapes if they are related to the investigation of the criminal ring.

"In legal terms, a witness must have knowledge of the event. Zhu might possess the sex tapes, but that does not mean he knows they have been used to extort officials," he said.

"The scandal … should be investigated independently," Si added.

Wang Peng, a lawyer who accompanied Zhu to a meeting with Chongqing police, said officers knocked on the blogger's door and requested a meeting late on Sunday.

"They did not inform Zhu in advance," he said.

Wang said Zhu asked four lawyers, including Wang, to accompany him if Chongqing police require similar meetings in the future.

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Cao Yin contributed to this story.

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