A POLICE superintendent told a court yesterday he feared a ''rowdy and emotive'' crowd demonstrating outside the New China News Agency (NCNA) on June 4 last year was about to force through police lines. ''I could tell they were getting ready to push through the police lines. I could see it coming,'' Chief Superintendent Lionel Lam Kin, deputy regional commander for Hongkong Island, told Eastern Court. He ordered police warnings to disperse peacefully to be issued but the pushing increased. Mr Lam was giving evidence at the trial of four June 4 protesters who allegedly took part in an unlawful assembly. The hearing will examine whether or not the summons against the four are in breach of the Bill of Rights. Part-time actor Chan Sau-sum, 39, student Wong Ching-man, 22, insurance agent To Kwan-hang, 24, and Choi Yiu-cheong, 25, an aide to Legislative Councillor Lau Chin-shek, all face a summons of unlawful assembly. Chan also faces a summons of theft and is alleged to have stolen Chief Superintendent Hung Hing-lun's beret. They have denied all the summons. The first day of the trial before Magistrate Alan Wright attracted a peaceful demonstration outside the court campaigning for the Public Order Ordinance to be amended and the summons to be dismissed. Deputy Principal Crown Counsel Arthur Luk opened his case in a packed courtroom by saying: ''If demonstrators resort to violence, they will be prosecuted and brought to justice.'' It is the Crown's case that in the early hours of June 5 last year about 30 police officers were injured. Martin Lee QC, representing Wong, To and Choi, plans to challenge the validity of Section 18 of the Public Order Ordinance on the grounds it was inconsistent with the Bill of Rights. It was agreed the legal arguments should be heard later in the trial. Chan is represented by Eric Kwok. For the Crown, Mr Luk said that on the evening of June 4 the Hongkong Alliance in Support of the Patriotic Democratic Movement in China held a candlelight vigil in Victoria Park in memory of the June 4 massacre in 1989. It was a peaceful assembly attended by about 20,000 people. However, at the end of the meeting some participants marched to the NCNA building in Happy Valley. Mr Lam, who was responsible for policing the protest outside the NCNA, said demonstrators asked to be allowed to march in front of the building. He agreed if they went in groups of 19 or less in accordance with general police policy. A Mr Yeung told Mr Lam he would accept the offer of small groups being allowed through. After groups went through without incident Mr Yeung and Mr Lam shook hands. But remaining demonstrators repeated the demand to be allowed to protest as a group. Articles such as plastic bottles were thrown and there was ''a tremendous noise'' of shouting. Four demonstrators (not the defendants) slipped through the police cordon and ran to the main entrance of the NCNA. They were subdued by police and taken to a police post behind the building. Two others were also detained at the post. The six were later released to cheering of the crowd. The case continues.