A judge was urged yesterday to order a stay of prosecution in the case of a teenager charged with molesting an 11-year-old girl, because the alleged victim could not be found. Barrister Sher Hon-piu, for Lau Ka-chuen, 17, argued that the absence of the girl - who has been sent back to the mainland by her parents - would prevent his client from having a fair trial. But prosecuting counsel Leslie Parry said a stay was not necessary because the prosecution would call a witness, testifying under immunity, who saw the alleged incident and videoed it with her mobile phone. Lau is alleged to have stripped the girl and sexually assaulted her in front of a group of other young people after she passed out from taking ketamine he had been distributing. Mr Parry said the prosecution would call the girl as a witness if it could. 'To say that we decline to call her is an unfair remark. We cannot call her because her father has refused to disclose her address.' He said the case could go ahead with the evidence of the witness, a 15-year-old girl. But Mr Sher said such a witness was less reliable than the victim, insisting that a victim's evidence was 'overwhelmingly important'. Deputy Judge Pang Chung-ping adjourned the hearing and he is expected to deliver his ruling today. Lau pleaded not guilty yesterday to one count of trafficking in ketamine and one of indecent assault. Mr Parry said in his opening speech that Lau was involved in giving out ketamine to the group of young people, who had gathered in a rear staircase of a building in Tin Yat Estate, Tin Shui Wai, in the early hours of April 27 last year. He said the group had sniffed the drug and the victim became unconscious.