On Thursday, as former Nassau County Executive Edward Mangano prepares to stand trial within the coming weeks on corruption charges, federal authorities unsealed an indictment alleging that Mangano's former chief deputy lied to the FBI about taking money from a contractor.

The two-count indictment for Richard Walker, 43, is the latest set of federal charges filed in recent years against a top-level operative in Nassau County politics, and comes after a an investigation of more than two years into allegations that Walker steered government contracts to donors.

According to prosecutors' filings, Walker, who is charged with obstruction of justice and making false statements, allegedly accepted a contractor's invitation to a University of Notre Dame football game and, upon Walker's return to New York, received a $5,000 cash payment from the contractor.

In 2017, according to prosecutors, when Walker learned that the U.S. Attorney's Office for the Eastern District of New York and the FBI had launched a grand jury investigation into public corruption in Nassau County, Walker allegedly told the contractor to conceal the payment from the grand jury.

Prosecutors said that Walker tried to meet the contractor to return the money, and that FBI agents observed him slip the contractor an envelope with $5,000 inside.

Walker was arrested on the charges on Thursday and pleaded not guilty at his indictment, according to a spokesman for the U.S. Attorney's Office for the Eastern District of New York. He was released on a $200,000 bond and is due back in court in May.

Walker's attorney, Brian Griffin of Foley Griffin in Garden City said the “contractor” mentioned in the government's papers is a 25-year friend of Walker's and that they had known each other before Walker had entered county government, though he declined to disclose the friend's name.

“The federal government's attempts to criminalize the personal relationships of public officials is troubling,” Griffin said.

Griffin also said that the “full forces” of the federal government were deployed to scrutinize donations to Walker, who also represented portions of Nassau County in the state Assembly from 2005 to 2009, and pore over “every contract he ever touched,” and that his client is not being charged with bribery or official corruption.

Walker's case has been assigned to U.S. District Judge Joan Azrack of the Eastern District of New York, who will also preside over the trial for Mangano and former Oyster Bay Town Supervisor John Venditto.

Assistant U.S. Attorneys Catherine Mirabile, Raymond Tierney and Lara Gatz, the prosecution team handling the Mangano and Venditto case, are also handling the prosecution against Walker.

Mangano and Venditto are accused of taking part in a pay-to-play scheme in which prosecutors say the two elected Republican officials helped local restaurateur Harenda Singh get government contracts as well as $20 million in indirect loan guarantees.

The scheme allegedly also included providing a $450,000 no-show job for Mangano's wife, Linda Mangano.

A no-show job also played a prominent role in the corruption against Dean Skelos, the former Republican majority leader in the state Senate; and his son, Adam Skelos.

In 2015, the Skeloses were convicted in 2015 of Hobbs Act conspiracy and extortion, honest services wire fraud conspiracy, and federal program bribery.

Walker, who was under investigation at the time, testified in the Skeloses' trial under a condition of immunity signed by U.S. District Judge Kimba Wood of the Southern District of New York that he helped the defendants seek a request for proposals for a partnership with a company that had Adam Skelos in its employ.

But last year the U.S. Court of Appeals for the Second Circuit threw out the conviction, citing a recent U.S. Supreme Court that requires prosecutors to provide a tighter definition of official acts in jury charges and that has also given some hope to other politicians who face corruption charges.

The U.S. Attorney's Office for the Southern District of New York is planning for a retrial of the Skeloses.