A SEX attacker once mistaken for the notorious Tuen Mun rapist yesterday lost his bid for an early release. Lun Kwok-keung, 22, was arrested in Tuen Mun when police were hunting a serial killer and rapist. Lam Kwok-wai was later jailed for life for three murders and eight rapes in the area. Last January, Lun pleaded guilty to indecently assaulting an 18-year-old woman under a flyover near Kai Man Path on November 26, 1993. He also admitted two counts of assault causing actual bodily harm to two police officers who arrested him. Lun was jailed for five years. Edward Mumford QC, for Lun, told the Court of Appeal that on the night of his crime, the sex attacker had just finished watching a film that reminded him of his brother's death. When he came across the young woman, he grabbed her from behind and then struck her in the face. When the teenager begged him to let her go, he ordered her to be quiet and take off her trousers. Lun assaulted her and then throttled her until she lost consciousness. When she recovered, the teenager spotted the police officers and cried out for help. As they tried to arrest Lun, he fought to escape. Mr Mumford argued that Lun's sentence was too long. He told the Court of Appeal the ruling was out of line with similar cases and should be reduced to about three years. Mr Justice Power, Mr Justice Bokhary and Mr Justice Mortimer rejected the plea. Mr Justice Power said: 'This was a determined attack on a young woman, late at night in an isolated area. It must have been a terrifying experience for her.'