A judge yesterday praised advances in DNA technology that brought a killer to justice almost six years after the crime. Three prison guards had to drag Cheung Siu-yui, 41, screaming and shouting from the dock yesterday after a Court of First Instance jury convicted him of the murder of Lee Yuk-fan, 24, in February 1995. During the struggle, he screamed 'I didn't kill her, I really didn't kill her', and claimed the police had framed him. But in imposing a mandatory life sentence, Mr Justice Colin Jackson said the jury's unanimous verdict made it clear they believed Cheung had murdered Lee in her bed. 'You went to her home in the middle of the night for reasons only known to you and in a violent struggle you overpowered her and applied enough pressure to her neck that she died,' he said. 'It is quite apparent to me that if it weren't for the recent advances in DNA technology and profiling, you would never have been brought to justice.' During the trial, the jury of three women and five men heard police arrested Cheung for the murder last year - his second arrest over the crime - after advances in DNA technology enabled them to unravel the clues left on Lee's body. There was only a one-in-374-billion chance that skin found under Lee's fingernails did not belong to Cheung, the court heard. And fibres found on tracksuit trousers recovered from Cheung's home matched those found on a T-shirt Lee was wearing when her body was discovered by her boyfriend on February 3, 1995. During the trial, Cheung, who previously had denied having any contact with the victim apart from delivering a gas bottle to her home, told how he had suddenly remembered he had encountered Lee in a local Jockey Club betting shop the day before her body was discovered. He said that although he was not able to remember if he was wearing the tracksuit trousers on that particular day, he did recall getting into a dispute with a stranger which would have ended in a punch-up if Lee had not intervened. It was during Lee's attempts to break the two men apart that she scratched him, the jury was told. The court also heard Cheung had fled to the mainland within three hours of filling out a questionnaire for police investigating Lee's death. The father-of-one claimed he was scared after he spotted a loanshark in the street and thought he could hide out for the next few years. Cheung was not handed over to Hong Kong authorities until October 17, 1998, and was arrested for Lee's murder. He was released due to a lack of evidence. But on August 27 last year he was rearrested after the new DNA technology matched skin cell samples taken from Lee's fingernails to Cheung. Before he was led away from the dock, Cheung's defence counsel, Munira Moosdeen, read from a letter in which Cheung said he had a family to support, including his wife, daughter and 65-year-old mother. Cheung's sister was present for yesterday's verdict and was told to be silent after yelling out to the jury that they had 'no conscience'.