Lawyers for a woman who alleges she was sexually assaulted by Prince Alwaleed bin Talal of Saudi Arabia say the case has not been properly handled by Spain's criminal justice system. The woman, known only as "Soraya", says she was assaulted on a yacht moored off the island of Ibiza in 2008. A spokeswoman for the prince denied the allegation and said he had not been to Ibiza for more than a decade. The case was shelved by an island court but has now been reopened. This followed a successful appeal by Soraya's lawyers. The judge is preparing a second official request to the Saudi authorities for assistance in formally questioning the prince. The nephew of Saudi King Abdullah, Prince Alwaleed bin Talal is a multi-billionaire with major investments in both Citigroup and NewsCorp. 'Something in my drink' "In our opinion, the Court of Instruction No 3 in Ibiza and the police did not follow full procedure in cases of alleged sexual abuse," the lawyers from Madrid-based firm Turiel and Beloqui told the BBC. "There are things that should have been investigated that were not - like questioning staff on the yacht and the guests, an analysis of the victim's clothes and so on," the lawyers wrote, describing the fact these steps were not taken as "very unusual". The claim that the case was not being pursued with proper rigour was dismissed by the Ibiza court in 2010, saying that the identity of the accused in no way affected its decision to drop the case that year. The court ruling cites insufficient evidence to proceed. Continue reading the main story “ Start Quote My daughter was in a terrible state, [...] scared to death, crying, awful” Mother of 'Soraya' Soraya, a Spanish-German model, was 20 at the time of the alleged attack on 13 August 2008 on board the 117-metre luxury yacht Turama. She told police she had begun to feel nauseous in the VIP zone of a local night club, where she believes something was slipped into her drink. She had been taken there by a man claiming to be a chauffeur for "an Arab prince" who was visiting the island. According to court documents seen by the BBC, Soraya sent the chauffeur an SMS text message at 05:12, saying: "I haven't drunk much but I think there was something in my drink." The model says she came round some hours later on board the Turama to find a man on top of her. She later identified the man as Prince Alwaleed bin Talal using images taken from YouTube. Forensic reports from a medical examination the following day revealed traces of a sedative and semen, but no physical injuries. A woman identifying herself as the mother of Soraya told the BBC her daughter had called on the morning of the alleged attack asking her to come and collect her from the island. "My daughter was in a terrible state, [...] scared to death, crying, awful," the woman said, responding to questions sent by email. "The Spanish justice system has treated this case very badly. In my view they did not want to get too involved because of who the accused was." A 2010 prosecutor's report says three men who were questioned by police during the investigation were unable to corroborate the model's version of events "in any way". The Saudi foreign ministry rejected an initial request from the Ibizan court to investigate, citing "an inability to identify the accused and a lack of solid evidence". This week, a spokeswoman for Prince Alwaleed's Kingdom Holding Company said the prince had never been informed of the 2008 court case, or that it was eventually shelved. In a statement, she also said the billionaire's travel records confirm he was with dozens of friends and family at the time of the alleged attack, nowhere near Ibiza. "There have been many examples of people impersonating Prince Alwaleed over the internet and elsewhere for their own purposes," Heba Fatani said in a statement. She called the allegations against him "salacious" and "completely and utterly false". The Audencia Provincial court in Mallorca - which has jurisdiction over Ibiza - has ordered the case to be reopened in order to ensure the prince can be questioned in accordance with Spanish law. Soraya's lawyers have urged him to provide a DNA sample to rule himself out of the inquiry.