Eight minor culprits behind a plot to murder former Democratic Party chairman Martin Lee Chu-ming and publishing tycoon Jimmy Lai Chee-ying yesterday pleaded guilty to attempts to cause injury. But two alleged masterminds denied charges of attempted murder. The trial, in which Tung Nga-man, 67, is said to have offered another suspected Hong Kong gangster, Yu Wai-shan, 63, US$1 million to organise the murder of the two prominent Hong Kong residents, began yesterday morning at Shenzhen Intermediate People's Court amid tight security. Journalists, including those from mainland government-controlled media, were barred. Some relatives of the defendants were also denied entry. Most of the defendants were rich businessmen, according to an assistant lawyer for one of the defendants. The motive for the murder plot is still unclear, but the prosecution said 'there was no smoke without fire' and suggested that some people might have offended others with their words in Hong Kong. Mr Lai's name was mentioned frequently in the hearing, but Mr Lee's was only rarely spoken. A source familiar with the hearing said this was because Mr Lee was a politically sensitive figure. Three more people have been charged in relation to the murder plot but will be tried in a separate case. Alleged masterminds Tung and Yu yesterday denied charges of attempted murder. But their alleged accomplices - Huang Fuhan, Zhan Zunshuo, Chen Shaoming, Chu Ying-wah (Zhu Yinghua in Putonghua), Li Hongzhuang, Tam Yaosong, Zhang Suiling and Xie Huijun - admitted attempts to cause injury. Chu and two others among the eight are Hong Kong residents. A handful of police officers and security guards guarded the courtroom and kept out journalists from Hong Kong and Guangdong. Sources said the judicial authorities were highly concerned about the trial because the murder plot might be connected with politics. Most of the defendants were arrested in August - the same month that Hong Kong police foiled the plot. Huang Nanhua, 50, who was tried separately in Hong Kong, was arrested on August 16 at a roadblock in Mong Kok carrying a pistol, five bullets and the personal details of Mr Lee and Mr Lai. The mainland gunman was jailed for 16 years after being found guilty of carrying a firearm and ammunition with intent to commit an arrestable offence. Huang's friend, Hong Kong resident Ho Wai-kam, 50, was jailed for three years for smuggling a gun and bullets into Hong Kong from Shenzhen. The Hong Kong court did not consider whether the gunman had tried to kill Mr Lee or Mr Lai. The trial continues today.