VIENNA — U.S. and British investigators have joined Austrian prosecutors in examining possible ties between a Vienna fund manager and disgraced financier Bernard Madoff, whose multibillion-dollar Ponzi scheme wiped out thousands of investors and charities worldwide, an official said Monday.

Gerhard Jarosch, spokesman for the Vienna public prosecutor's office, told The Associated Press his office is aiding the U.S. Justice Department and Britain's Serious Fraud Office in separate investigations of Bank Medici AG and its chairwoman, Sonja Kohn.

Both Kohn and Medici also have been the focus of a fraud investigation in Austria since February, Jarosch said, stressing that Kohn has not been charged with any criminal wrongdoing.

"I can confirm that we are assisting the U.S. and British authorities in their investigations of Mrs. Kohn in connection with the Madoff case," he told AP. Jarosch declined to elaborate or say whether Kohn has been questioned by investigators from either country.

Kohn, 60, has an unlisted phone number and could not be reached for comment Monday. Her attorney, Andreas Theiss, said she was not giving media interviews — but he insisted she had no personal dealings with Madoff.

"It's just not true," Theiss told AP.

"There are some investors who lost money. Even the Kohn family lost a lot of money, full stop," he said. "That wasn't caused by Ms. Kohn. That was caused by Madoff."

"Ms. Kohn is saying she never, ever got money from Mr. Madoff ... and there's no evidence of any payments like that," Theiss added.

Prosecutors suspect that Madoff paid Kohn commissions in exchange for allegedly funneling billions of dollars in European investments to Madoff, according to a person with knowledge of U.S. involvement in the case. The person spoke on condition of anonymity because the investigation was ongoing.

Madoff was sentenced last week to 150 years in prison for swindling thousands of investors in a massive Ponzi scheme.

In London, the Serious Fraud Office would not comment, saying it does not identify suspects until they are formally charged. A spokeswoman for the U.S. Attorney's Office for the Southern District of New York also declined to comment.

Vienna-based Bank Medici disclosed in December that it had suffered huge losses it blamed on Madoff. It said nearly all of its Herald USA Fund and Herald Luxemburg Fund — with a total volume of $2.1 billion — were invested with Madoff.

In subsequent interviews with Austrian media, Kohn has characterized herself as one of Madoff's biggest victims and has described Medici's ordeal as a personal and professional tragedy.