NEW YORK (Reuters) - A federal judge in Manhattan on Monday refused to dismiss fraud charges against a former Platinum Partners hedge fund executive and a former union leader for New York City prison guards, who claimed their indictment was based on illegal wiretaps.

The defendants, Murray Huberfeld and Norman Seabrook, said the indictment was based improperly on phone calls involving Huberfeld that were overheard by law enforcement officers probing a separate fraud, involving high-level New York City police officials in an illegal liquor distribution scheme.

But the judge, Andrew Carter, said those officers were not required to ignore evidence of another crime in “plain view,” even if it were unrelated to the fraud targeted by the wiretaps.

Prosecutors in June 2016 accused Seabrook, the former president of the Correction Officers’ Benevolent Association, of investing $20 million of union money with Platinum in exchange for kickbacks from Huberfeld.

Both men have pleaded not guilty to charges of honest services fraud and conspiracy. Huberfeld had initially sought to dismiss the indictment, and Seabrook later joined him.

Henry Mazurek, a lawyer for Huberfeld, said in an email: “While we respect the court’s decision, the issues we presented in the pretrial motions will continue to be litigated at trial.”

Paul Shechtman, a lawyer for Seabrook, declined to comment.

The separate fraud involved Hamlet Peralta, the former owner of the now-closed Hudson River Cafe in Harlem, who was sentenced on Friday to five years in prison after pleading guilty to running a $12 million Ponzi scheme.

Prosecutors said two of his investors, Jona Rechnitz and Jeremiah Reichberg, who both raised money for New York City Mayor Bill de Blasio’s 2013 campaign, bribed senior police officers with luxury trips and other gifts in exchange for favors.

Rechnitz has pleaded guilty and is cooperating with prosecutors, while Reichberg has pleaded not guilty.

No charges were brought against de Blasio, and a related probe into his fundraising was closed in March.

Last December, seven people affiliated with Platinum, including founding partner Mark Nordlicht, were charged with running a $1 billion fraud that prosecutors said was “like a Ponzi scheme.” Nordlicht has pleaded not guilty.

The case is U.S. v. Seabrook et al, U.S. District Court, Southern District of New York, No. 16-cr-00467.