After nearly three hours, the fourth interrogation of Prime Minister Ehud Olmert by investigators from the National Fruad Unit came to a close Friday afternoon. The session, at the prime minister's official residence, began at 10:00 a.m. and lasted 45 minutes longer than the original allotted time of two hours after Olmert gave his consent. A "source close to Prime Minister Ehud Olmert" told law enforcement authorities where to find documents which showed how the premier allegedly received hundreds of thousands of dollars from Long Island businessman Morris Talansky, former National Fraud Unit chief investigator Dep.-Cmdr (ret.) Boaz Guttman told The Jerusalem Post on Thursday. Guttman said the source first chose to alert State Comptroller Micha Lindenstrauss to the Talansky affair several months ago, and that Lindenstrauss in turn notified the police. "Lindenstrauss was told about the whole story of Talansky, and he was told where to find the documents of Shula Zaken [Olmert's former bureau chief], by inside sources. The state comptroller received inside, quality information. Perhaps the source held a grudge against Olmert," Guttman said. "After receiving the tip, the Comptroller's Office investigated, and in turn alerted the police." A spokesman for the State Comptroller's Office confirmed it had been the first to alert police to the Talansky suspicions, but denied that the information came from sources close to Olmert. "It's accurate that our office first found the material," the spokesman said. "I don't think it's true that Olmert's inside people gave it to us. We found the material through an independent check." But Guttman insisted that the information could not have been found randomly. "Two years ago, the police had no idea about Talansky. It was stuck on weaker investigations like the Cremieux home case. It didn't know where to get hold of the documents. Suddenly, it knew where to look," he said. After being notified by the state comptroller, the police had to independently obtain court orders to seize the relevant case material, as it is "forbidden by law for police to directly use evidence received from the state comptroller," Guttman added. Friday's interrogation of Olmert could be the last time police need to speak to the premier, a National Fraud Unit spokeswoman said Thursday. "It depends on the dynamics of the questioning session. If detectives exhaustively run through the questions with Olmert, an additional date [for questioning] may not be necessary," the spokeswoman said. Detectives were expected to ask Olmert to explain documents related to the Rishon Tours investigation, in which police say receipts have been uncovered showing that Olmert double-billed charities and a government ministry for the same flights, placing the excess in a specially created account which he used to fund family travel. Guttman said Friday's interrogation could easily obtain all that the police would need to hear from Olmert regarding the Rishon Tours allegations. "There isn't much to talk about. The Rishon Tours case is based on documents, not testimonies. All of the documents are in police hands. All the detectives need to do is ask Olmert, is this your signature? Is this your account?" According to Guttman, prosecutors can formally charge Olmert by September 1 over both the Talansky and the Rishon Tours affairs. He added that senior law enforcement officials involved in the Olmert investigations have indicated that an indictment should take very little time. The fact that prosecutors have accompanied police from the start of the Talansky investigations should make the indictment process even swifter, Guttman said, because there is no need for police to "transfer" the cases to state prosecutors. "The state prosecutors in this case, such as [State Attorney] Moshe Lador and [Jerusalem District Attorney] Eli Abarbanel, do not need to be qualified on how to use the documents from the investigation in court. Abarbanel is familiar with Olmert from previous investigations," Guttman said. "State prosecutors have sat with the police from day one, poring over the evidence, looking at the documents. Everyone here knows what to do." Talansky's preliminary court appearance in May will make the indictment process even more efficient, Guttman said, because Olmert's lawyers have already received most of the material needed to mount a defense, robbing them of the claim that they need more time to prepare before a trial begins. Guttman said that between now and September, Olmert will receive one opportunity to challenge or delay an indictment. "According to the law, every suspect who is about to be indicted receives a notice from the prosecution notifying him of this, giving him 30 days to try to convince prosecutors that there is a reason why the indictment shouldn't be served. During this period, Olmert's lawyers could call a hearing and argue that there are flaws in the way police managed the investigation. "If prosecutors agreed, it could be dangerous, as police would be ordered to go back and investigate again. On the other hand, this can backfire on the suspect, because it could make the case against him even more severe," he said. Also, state prosecutors are unlikely to accept arguments of police irregularities, as they have accompanied the National Fraud Unit from the start, Guttman added.