Other users have been wary of casting the case as a free-speech issue, partly because they sense that the police crackdown may have strong public backing and partly because Hong Kong laws allow the police to prosecute people who distribute pornography.  Some say the backlash from the public could be worse than the crackdown by the police if Internet users oppose it too vocally.  “If we listen to radio talk shows and so forth, there are people calling in who say that Internet users are unreasonable and want to pass around dirty pictures,” said Charles Mok, the chairman of the Hong Kong chapter of the Internet Society, an international advisory group on Internet standards.  Mr. Mok took a somewhat sympathetic tone toward authorities, noting that just as the police could not ticket every traffic offender, they could not charge everyone who distributed pornography, but did have an obligation to address cases that caught the community’s attention, like videos and photos that appear to show famous singers engaged in sex acts.  Mr. Mok did not join Sunday’s march, which the police estimated at 230 people and organizers estimated at more than 400.  One of Hong Kong’s most popular singers, Gillian Chung, who has a following of girls in their early teens and younger and who has been prominently featured in ads for Hong Kong Disneyland, seems to appear repeatedly in the photographic material. Ms. Chung is part of a duo known as the Twins.  At a brief news conference on Monday, Ms. Chung neither confirmed nor denied that she appeared in the images, but she said she had been “naïve” in her youth and regretted causing distress to her family and fans. The date of the images is unclear, but they appear to have been taken over the last several years.  When a few photos began to circulate on the Internet in late January, the Emperor Entertainment Group, the promoter of Ms. Chung and several other singers involved, suggested that the photos had been altered to place the stars’ faces on other women’s bodies in the videos and photographs. Spokesmen for Emperor Entertainment declined to comment on the dispute.  Late Tuesday, in an e-mail reply to questions, the Hong Kong police confirmed that they had arrested nine people and said that two had been charged so far with “publishing obscene articles” and one had been charged with “access to a computer with dishonest/criminal intent.”  The police declined to address the question of selective enforcement except to say that “any enforcement action taken by the police is in accordance with the laws in Hong Kong.”  Some observers say they see the current cases as part of a toughening of Hong Kong police policies. The arrests coincide with preparations for six Olympic equestrian events to be held in Hong Kong in August.  Jackie Hung, the vice convener of the Civil Human Rights Front, a broad coalition of nongovernmental groups in Hong Kong, said she knew of 37 protesters arrested last year at nonviolent demonstrations.  The crackdown contrasts starkly with Hong Kong’s recent past. When about 500,000 people protested on July 1, 2003, against a proposal for strict internal security laws, the police arrested no one. Afterward, the government withdrew the proposal.  Hong Kong media reported this week that a video store across the border in mainland China was selling CDs of the singers’ explicit videos and photos for $2.70 each, but was promptly closed by mainland officials. Discussions of the videos and photos have flooded Internet forums in Hong Kong and the mainland.  The photos and videos appear to show a well-known male Hong Kong singer and record producer, Edison Chen, in separate scenes with at least six women, four of whom are also well-known singers. In a video released last week, Mr. Chen apologized “to anyone who has been affected” and asked the public to delete any copies of the photos.  “The lives of many innocent people have been affected by this malicious and criminal conduct, and in this regard I am filled with pain, hurt and frustration,” Mr. Chen said.  According to the police, Mr. Chen took his laptop computer to a local computer repair shop, and the computer’s memory was copied there. An employee at a downtown computer store, eLiTe Multimedia Ltd., who only gave his last name, Yeung, said on Tuesday that a former employee had been arrested, but he declined to elaborate, citing the police investigation.  The current scandal has led Hong Kong tabloids to run reports in the last several days of supposed plans by gangsters to “teach a lesson” to Mr. Chen and perhaps even kill him. Organized crime has long played an important role in Hong Kong’s entertainment industry.  Mr. Chen has left Hong Kong but plans to return this weekend and hold a news conference, said Mavis Leung, his spokeswoman, who declined to elaborate.  A version of this article appears in print on , on Page C3 of the National edition with the headline: Internet Sex Video Case Stirs Free-Speech Issues in Hong Kong. Order Reprints| Today's Paper|Subscribe
Several arrests in Hong Kong for posting sexually explicit images of what appear to be some of Asia’s best-known pop stars has led to a debate over free speech on the Web.