BUSINESSMAN Cheng Shui, who hired an illegal immigrant to shoot someone in Hong Kong, was found guilty and sentenced to 13 years' jail yesterday. It is rare for court to sit on weekends, but Mr Justice Jerome Chan decided to continue the hearing on Saturday and yesterday because some jurors told him they had to leave Hong Kong for personal reasons. The seven-member jury returned a verdict that Cheng was guilty of possessing arms and ammunition without a licence and conspiracy to murder. Mr Justice Chan said Cheng, 39, had committed ''a very serious offence''. He said the number of people committing such offences was on the increase and deterrent sentences had to be given ''to show that society could not stand such kinds of crime''. Cheng, through a third party, engaged Yiu Siu-ping, 25, for $100,000 and gave him a loaded pistol to kill businessman Li Man-chu in 1992. On May 29, 1992, Yiu, a martial arts instructor from Sichuan, was taken to Lockhart Road to wait for Li and kill him. When Li emerged, Yiu approached him but got cold feet. After the collapse of the plan, Yiu was on his way back to China when he was searched by police on patrol in Lau Fau Shan and revealed the murder plot to them. Yesterday's verdict was announced without the Crown prosecutor, Christopher Coghlan, being present. The jury was ready to deliver its verdict at 2.45 pm, but Justice Chan waited until 3.30 pm for Mr Coghlan before appointing the police officer-in-charge to replace him.