The disciplinary watchdog in Chongqing has promised a thorough investigation into the sex-tape scandal that led to the dismissal of 11 local officials after the whistle-blower in the case said more, still-unnamed officials are involved in the case.

"We've made it clear from the start of the scandal that every official involved will be investigated and punished if found guilty of discipline or law violations," an official from the Party Discipline Inspection Commission in the municipality was quoted by Xinhua News Agency as saying on Thursday.

Ten mid-ranking officials in Chongqing, including district- and county-level Party chiefs and board chairmen at State-owned enterprises, were removed from their posts on Jan 25 for their involvement in the scandal. A criminal ring is suspected of hiring women to seduce officials who were then extorted.

The criminal ring has been broken up, and several alleged conspirators have been arrested or placed under house arrest, Chongqing police said earlier this week.

The official with the disciplinary authority said it took time for investigators to collect related evidence because the videos were made about four years ago, and the authority will ensure that results of the investigation withstand the scrutiny of society and history.

The statement was made after Zhu Ruifeng, a Beijing freelance blogger and whistle-blower in the scandal, claimed that even more high-ranking officials are involved in the case.

In November, Zhu posted a video online in which Lei Zhengfu, then the Party chief of Chongqing's Beibei district, was having sex with an 18-year-old woman.

Lei was removed from his post less than three days after the sex tape appeared online.

He will be prosecuted later on bribery and other corruption charges, the disciplinary watchdog said.

Zhu said that the board chairman of a State-owned company in Chongqing was another official involved in the scandal.

"There are still some clues (about more officials involved in the scandal) in my hands, and I will make them public after my investigation and verification," Zhu said in his micro blog.

Zhu rejected demands from police officers from Chongqing, who visited him in Beijing, that he surrender the videos, saying he wanted to protect his Chongqing police source from whom he obtained the videos.

He said he believed Chongqing police wanted to use the videos to discover the identity of the source.

Chongqing police rejected Zhu's claims, saying they want to visit him to get more evidence about the criminal ring.

Police said Zhu obtained the sex tape he later released online from Xu Sheqin, one of the suspects in the criminal network.

Police said Xu had a conflict in November with Xiao Ye, a key member of the network, over money, and Xu went to Beijing to give the videos to Zhu in retaliation.

However, Zhu said he obtained only one sex video from Xu. He obtained the other six from his source inside the Chongqing police.

Chongqing police have arrested Zhao Hongxia, the woman who allegedly appeared in the sex tap with Lei, according to Zhao's lawyer, Zhang Zhiyong, of the Zhihao Law Firm in Chongqing.

Xiao allegedly arranged for Zhao — his lover — to seduce the officials, and then secretly filmed them with hidden cameras.

"She told me she was brainwashed and was told she could help improve the company's performance by doing this," Zhang said in a telephone interview.