NEW YORK (Reuters) – Lawyers defending the former head of New York City’s correction officers’ union and a co-founder of defunct hedge fund Platinum Partners in a federal bribery trial told jurors on Tuesday that prosecutors’ star witness was a liar.

The witness, Jona Rechnitz, is expected to testify that he helped arrange bribes to Norman Seabrook, who once led the Correction Officers’ Benevolent Association, in exchange for the investment of $20 million of union funds in Platinum. Rechnitz has pleaded guilty in connection with a federal corruption investigation that has led to charges against police officers and others, and is cooperating with prosecutors.

Seabrook’s lawyer, Paul Shechtman, told jurors in opening statements in Manhattan federal court that Rechnitz, a California-born real estate developer, was “a serial liar, a pathological liar.”

Henry Mazurek, who represents Platinum co-founder Murray Huberfeld, said Rechnitz was seeking a “get out of jail free” card.

Seabrook and Huberfeld, both 57, are charged with honest services fraud and conspiracy.

Their lawyers spoke after Assistant U.S. Attorney Martin Bell laid out the case for the prosecution, telling jurors that Seabrook and Huberfeld worked out their bribery scheme after Rechnitz introduced them in 2013.

Bell said Seabrook agreed to have the union invest in Platinum, and Huberfeld agreed to arrange for Seabrook to get kickbacks from the fund. Huberfeld no longer had an official position at Platinum at the time, but Bell said he still wielded influence.

In 2014, Seabrook caused $20 million of the union’s pension and operating funds to be invested in Platinum, Bell said. In December of that year, Rechnitz handed Seabrook $60,000 in cash stuffed in an $800 Salvatore Ferragamo bag, and Huberfeld had Platinum reimburse Rechnitz, Bell said.

“Pure greed brought these men together,” Bell said.

Bell acknowledged that Rechnitz was “a wheeler and dealer” who had broken the law. However, Bell said, Rechnitz’s testimony would be corroborated by other evidence.

Shechtman and Mazurek both described Rechnitz as a skilled political operator.

Shechtman told jurors that Rechnitz once had a lane of the Lincoln Tunnel shut down for his friends to use, while Mazurek said he had the ear of mayor Bill de Blasio. De Blasio’s office did not immediately respond to a request for comment.

Last December, seven people affiliated with Platinum were charged with running a $1 billion fraud. They have pleaded not guilty. Platinum has been placed under the control of a court-appointed receiver.