A serial rapist who filmed his knifepoint sex attacks on three female students, one 12 years old, was told by a High Court judge yesterday he could face life in jail. Deputy Judge Alan Wright told Cheung Lai-man, 34, he had a life term in mind but would reserve sentencing until he had read two psychiatric reports evaluating whether the defendant posed an 'ongoing threat' to society. Cheung pleaded guilty in the Court of First Instance yesterday to the three rapes, which took place between November 1997 and May last year while the victims, aged 12, 20 and 21, were on their way to school or college. He denied raping a 17-year-old girl in a rooftop room in a house on a Chai Wan estate in 1992 and two charges of robbery involving one of the three rape victims. Deputy Director of Public Prosecutions Arthur Luk Yee-shun, SC, along with government counsel Alice Chan agreed to leave the charges on file. The court heard Cheung raped the 12-year-old in bushes in Sha Tin, the 20-year-old in a make-shift shelter on a hillside in Sha Tin and the 21-year-old in bushes in Tseung Kwan O. Mr Luk told the court that on each occasion Cheung ambushed the victims wearing a balaclava and gloves, threatened them with a knife, blindfolded them and tied them up with plastic strips and a metal chain. He also threatened to kill them if they refused to submit to his demands, the court heard. Mr Luk said Cheung recorded the sex acts on video, and kept the tapes at his home in Tsuen Wan, where he lived with his wife. The court heard Cheung attacked the 20-year-old, the last of his three victims, on May 28 last year in a makeshift shelter he had set up. He was arrested the same day when the victim's younger sister heard screams near their family home in Sha Tin and their father saw a naked figure standing inside the shelter and alerted police. On arriving, officers saw Cheung hurrying down a hillside from the shelter carrying a rucksack and gave chase. When they had subdued him, the court heard police found a knife, two video cameras, each with a tape inside, a black blindfold, adhesive tape, a lighter, a metal chain and two plastic strips inside the rusksack. He also had a radio receiver used for checking the movements of patrolling officers. When interviewed by the police, Cheung admitted he had grown familiar with the routines of two of his victims, but said that he had laid in wait for anyone to pass by when he attacked the 21-year-old. Deputy Judge Wright asked prosecutors to obtain impact statements from the victims as he believed they could help with sentencing. Mr Luk said a report obtained on the 21-year-old victim showed the depth of 'her inner turmoil' as a result of the attack was not yet fully known. Deputy Judge Wright adjourned sentencing until October 7 for psychiatric reports.