Detectives from the National Fraud Unit are "trying to figure out how [Prime Minister Ehud] Olmert came up with his explanations for where all of the money he received from [New York financier Morris] Talansky went," a senior former law enforcement official said on Tuesday. The source described the prime minister's account of the cash's destinations as unconvincing. "Olmert said the money went to cover deficits, but he has shown no proof for that. Some fictitious accounts may also be involved," the source said. Olmert will be questioned for a second time in Jerusalem on Friday morning for one hour, the Israel Police announced on Tuesday. Olmert's attorneys took four days to respond to a police request to set a time and place for the additional interrogation session, in what the source described as a deliberate play for time with the aim of first getting hold of materials from the police investigation. The prime minister's legal team is expected to receive access to case materials on Friday so they can cross-examine Talansky when he takes the stand for a preliminary testimony scheduled for Sunday, the source said. But the lawyers have lost their battle to obtain the case material before Olmert's interrogation, he said, which was good news for the police, as "the prime minister will be interrogated without the help of 25 advisers who can use the material to cook up a version of events that can soften the very dark picture that currently stands." Olmert's lawyers "will probably ask the Jerusalem District Court to postpone Talansky's testimony for a few days, arguing that they need more time to analyze material for the case. I would expect Olmert's lawyers to seek a delay of a day or two to study the material - and they have good cause for making such a request. I think the Jerusalem District Court may grant it," the source said. The lifting (possibly on Wednesday) of the partial media ban over details of the criminal investigation will lead to further revelations in the case, including the extent of the funds in question, the source indicated. "The public will learn that more money than they think is involved. There's lots of money here," he said. "Despite official statements, the police are not really interested in Olmert's two terms as mayor - they're focusing on his time as Industry, Trade and Labor Minister, between 2003 and 2006," the senior former law enforcement official added. "There is no question that we are talking about a bribery investigation. There are word games being played by authorities to try and soften things up, because the prosecution and the police have been burned in the past, and they want to be cautious. But this is about bribery," he said. On Tuesday evening, Talansky was interrogated again by the National Fraud Unit at its Bat Yam headquarters. Barring unforeseen circumstances, Talansky's pre-trial testimony will be heard on Sunday, according to a decision handed down Tuesday by the Supreme Court. The court paved the way for Talansky's testimony by rejecting the appeal by lawyers representing Olmert and his former bureau head Shula Zaken, against a lower court decision granting the state's request to question Talansky in court even though no indictment has been issued. But the lawyers reportedly still had one ace up their sleeves that could lead to the postponement of the testimony. The reports said that Olmert's lawyers - Eli Zohar, Nevot Tel-Tzur and Ro'i Blecher - and Zaken's lawyer, Micha Fetman, planned to submit a request to the Jerusalem District Court on Wednesday to postpone the testimony, arguing they would not have enough time to review the evidence and prepare themselves for their cross-examination of the state's key witness. The lawyers themselves refused to say so openly. Asked after the Supreme Court rejected the appeal what his next step would be, Tel-Tzur would only say, "We'll do the right thing." Fetman told The Jerusalem Post it was too early to say what the next step would be. "It depends on the amount of evidence I am given," he said. "If it's 20 pages, I will not ask for more time. If it's 20 files, I will." It is no secret that since the investigation began, police have gathered a great deal of evidence from their investigations of Talansky, Uri Messer - Olmert's close friend and private attorney - and others. Until Tuesday, the lawyers for Olmert and Zaken had refused to take any of the evidence, even though most of it had been available to them since May 11, following the Jerusalem District Court decision to allow Talansky's testimony to be heard. According to a Justice Ministry official, the lawyers had picked up the investigation material from the Jerusalem District Attorney's Office by late Tuesday evening. The prosecution withheld material that it did not want Olmert or his lawyers to see before police question the prime minister on Friday. After that interrogation, the state will hand over that material, too. During Monday's Supreme Court hearing on the appeal, State Attorney Moshe Lador said the state might also withhold certain other material, but would inform the lawyers of precisely what this involved. Asked whether the state would object to the lawyers' request for a postponement of the pre-trial testimony, the Justice Ministry spokesman said it depended on various factors, including how much time the lawyers asked for. He added that the prosecution would also want to hear Talansky's opinion on the matter. Talansky has insisted on returning to the US no later than May 27. However, the state can force him to remain in Israel.