Federal investigators are currently scrutinizing New Jersey Senator Bob Menendez amid allegations that he received gold bars valued in the hundreds of thousands of dollars from a convicted felon for assistance, as revealed in a recently published report.

A federal grand jury convened to attempt to determine if corruption charges should be brought against the long-time lawmaker and senior New Jersey senator, NBC's local New York affiliate reported Wednesday. Witnesses have begun to testify.

At issue are Menendez's ties to New Jersey real estate tycoon and ex-bank chairperson Fred Daibes. FBI and national tax investigators are probing if Daibes gave Menendez's wife, Nadine Arslanian, gold bars worth up to $400,000.

The exchange took place at the same time that Daibes was under federal investigation for bank fraud, charges that could have led him to spend a decade behind bars, NBC reported. A legal expert told the news outlet that it could be criminal if Menendez agreed to contact Justice Department officials about the case for the gifts.

"For purposes of the Federal Extortion Act, it makes no difference if the senator took an official act so long as he accepted the money and there was knowledge the money was in exchange for that official influence, even if he never carried out what he had promised he would do," said NBC legal analyst Danny Cevallos.

Menendez disclosed that his family received the gold bars in 2020, but after the investigation into Daibes had begun, said NBC.

New Jersey’s U.S. Attorney’s Office agreed last year to allow Daibes to plead guilty to one criminal charge and serve probation. He had faced dozens of bank fraud charges related to a $1.8 million loan from Mariner’s Bank, where he was chairperson.

Daibes' sentencing has been delayed three times in the past year by U.S. District Court Judge Susan Wigenton. His attorneys have denied he is cooperating with federal prosecutors against Menendez, according to NBC.

But the gold bars exchange is just one part of the probe, said NBC. Authorities are also examining whether Menendez or his wife accepted gifts from IS EG Halal.

The start-up company won a lucrative contract with the Egyptian government to conduct all halal inspections for the U.S., despite not having any experience in the field.

Investigators are seeking to determine whether Menendez used his seat as Senate Foreign Relations chairperson to bolster the New Jersey company’s bid in exchange for gifts.

Menendez and IS EG Halal have denied any wrongdoing.