JERUSALEM - Police questioned Prime Minister Ehud Olmert yesterday for a second time in a corruption case that threatens his political survival and Israeli efforts to advance fragile peace moves with Syria and the Palestinians.

Olmert was questioned in his Jerusalem residence as part of an investigation into whether he illicitly took up to $500,000 in cash from the chief witness in the case, American Jewish businessman Morris Talansky.

The investigation is still in progress, and no charges have been filed against Olmert. Detectives and state prosecutors are exploring the possibility he took bribes, violated campaign-funding laws, and laundered money, police have said.

Olmert has acknowledged taking money from Talansky for political campaigns, but he said his campaign finances were the responsibility of longtime confidant Uri Messer, who was questioned again Thursday. Olmert has denied wrongdoing and vowed to resign if indicted.

National Fraud Squad investigators interrogated Olmert yesterday for an hour, police spokesman Micky Rosenfeld said. Olmert was last questioned two weeks ago for a similar length of time. Rosenfeld would not disclose details of the interrogation.

Top police officials, speaking on condition of anonymity because they were not permitted to disclose information on the investigation, said Olmert answered all questions posed to him.

They said he would be questioned a third time within the next week.

The allegations span 12 years beginning in the 1990s when Olmert was mayor of Jerusalem and extending through his tenure as minister of industry and trade, which ended in 2006, police have said.

Police have raided city hall and the ministry, carting away documents as part of their investigation.

Talansky insists he received nothing from Olmert in exchange for the money. He referred questions to his attorney, Jacques Chen, who denied that Olmert intervened on Talansky's behalf in connection with the technological project.

The investigation is the fifth into Olmert's conduct since he became prime minister two years ago. All the allegations relate to cases that took place before he became prime minister. No charges have been filed, and one of the cases has been closed.