National Fraud Unit detectives returned to Israel on Saturday with findings pertaining to the fresh criminal investigation into Prime Minister Ehud Olmert, police have confirmed. The latest investigation was launched in May after police said they found evidence showing that Olmert billed multiple donors and organizations for the same overseas trips over several years, and had used the excess - tens of thousands of dollars - to pay for personal flights abroad for himself and family members. A police spokesman said officers had carried out "a number of activities" linked to the new investigation. The officers were originally sent abroad in June to obtain documentation of the numerous bank withdrawals and transfers New York businessman Morris Talansky says he made to give Olmert hundreds of thousands of dollars. So far police say Yad Vashem, the Simon Wiesenthal Center, the Soldiers Welfare Association and the Industry, Trade and Labor Ministry were all double-billed by Olmert. Meanwhile, Shula Zaken, Olmert's trusted former bureau head and secretary, is likely to end her silence soon and begin telling police detectives what she knows about the hundreds of thousands of dollars Olmert is alleged to have received from Talansky, a former Israel Police chief investigator said on Sunday. "I think there's going to be a turnaround with Zaken soon," Cmdr. (ret.) Moshe Mizrahi told The Jerusalem Post. "I don't believe she will continue to be willing to pay for this alone. Otherwise she will take the fall for this affair and after a lengthy trial process could end up in jail. It would be a kamikaze act by her to remain silent, especially since her own notes document her handling Talansky's money," Mizrahi said. Zaken has so far refused to cooperated with National Fraud Unit detectives, despite being called in for questioning on numerous occasions. In a leaked transcript of a May 2 police interrogation of the prime minister which appeared in Maariv on Sunday Olmert struggled to recall key facts in his answers, and repeated the phrase "I don't remember" no fewer than 36 times. "With your permission, we'd like to focus on the money you received from Talansky while you served as industry, trade and labor minister," Ch.-Supt. Iris Barak said during the interrogation at Olmert's residence in Jerusalem. "I don't recall receiving donations," replied Olmert. At another point in the transcript, Olmert is quoted as saying, "I'm saying all of this isn't true. He [Talansky] gave me donations, checks, but not cash." The prime minister was asked to respond to evidence that Talansky had used his credit card to pay for Olmert's stay at the Ritz-Carlton Hotel in Washington DC. "I don't remember but such things could have happened. Because during our relations it could be that I delivered a lecture to a forum which he [Talansky] was interested in, and he covered my stay," said Olmert. "Was there was one such conference? Or more?" asked Barak. "I can't recall," Olmert replied. When confronted with an e-mail seized from Zaken's personal computer by police which said Talansky had transferred $72,5000, Olmert replied, "This tells me nothing. These are her notes. I don't remember this." Asked whether he had connected Talansky with business figures in the past, Olmert said, "I really don't remember. There could be a few times he turned to me. But I don't remember..." "Olmert doesn't remember a thing during the interrogation. But the prime minister's lawyers expect Talansky to remember events from 20 years ago during his cross-examination," said Mizrahi. The former chief investigator said state prosecutors may drop bribery charges from Olmert's charge sheet, choosing instead to focus on the charges of illegal receipt of funds and violation of public trust. Mizrahi said state prosecutors were right "not to be moved" by contradictions in Talansky's testimony on Tuesday, saying, "Olmert's problem is not just what Talansky says. There is formal and informal documentation of the money transfers in question. There is Uri Messer's [Olmert's close associate] testimony. And these are very serious things. In the transcript of Olmert's interrogation, we can see that the investigators were smart enough to ask Olmert whether he considered Zaken and Messer to be credible people, and he answered in the affirmative, effectively giving his blessing to Messer's testimony against him and Zaken's records. He admitted they are credible."