James Comey, Director of the Federal Bureau of Investigation (FBI), testifies during a House Permanent Select Committee on Intelligence hearing concerning Russian meddling in the 2016 United States election, on Capitol Hill, March 20, 2017 in Washington, DC.

WASHINGTON – FBI Director James Comey returns to Capitol Hill on Wednesday, where questions about possible ties between Russian officials and associates of President Trump's campaign are likely to dominate a Senate Judiciary Committee hearing.

It is Comey's first public testimony in more than a month. In March, Comey made headlines for confirming to another congressional panel that the FBI was in the midst of months-long inquiry into possible collusion between associates of the Trump campaign and Russian operatives.

The U.S. intelligence community has blamed Moscow for orchestrating a campaign to hack Democratic political organizations and release stolen information to undermine faith in the democratic process and candidate Hillary Clinton's campaign. The FBI's investigation of the hack subsequently expanded to included possible "coordination" involving Trump associates, but Comey has declined to elaborate on whether any such evidence has been uncovered.

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Comey did acknowledge, however, that the Russians appeared to use a third party — what he called a "cutout" — in its communications with WikiLeaks, which published internal communications obtained in the hack of the DNC. The identity of the third party was not disclosed.

Also in his last Capitol Hill appearance, before the House Intelligence Committee, Comey also delivered a definitive repudiation of Trump's claims that the Obama administration had wiretapped the president's New York offices in advance of the 2016 elections. "The FBI and the Justice Department have no information to support'' the president's assertions, Comey said during the more than five-hour session.

Since then, at least two former Trump advisers – Michael Flynn and Carter Page – have been the subjects of fresh scrutiny about their Russian ties.

Flynn, who was fired as Trump's national security adviser, is now under investigation by the Pentagon Inspector General for failing to inform Defense Department officials about seeking payments from foreign governments.

In February, Flynn registered retroactively as a foreign agent. He disclosed that he had earned $530,000 from a Dutch firm with ties to Turkey's government. Documents released by Rep. Elijah Cummings, the Maryland Democrat and ranking member of the Oversight Committee, also show that Flynn took more than $33,000 from the Kremlin-backed RT television network for a 2015 speech in Moscow. Russian President Vladimir Putin also attended the event.

Rep. Jason Chaffetz, R-Utah, chairman of the House Oversight and Government Reform Committee, last week called on the Army to determine if Flynn had violated the law and should be required to repay the government. Flynn, "by all appearances," violated federal law by accepting payments from foreign governments without obtaining prior approval, Chaffetz said.

Last month, the Washington Post also disclosed that the FBI had obtained a secret court order last summer to monitor the communications of Page, an adviser to then-candidate Trump, because the government had reason to believe Page was acting as a Russian agent.

Page has denied any wrongdoing and Flynn has sought immunity from any possible prosecution. Both the House and Senate Intelligence committees, in the midst of continuing Russia probes, have indicated that it is too early in their investigations to cut a deal for Flynn's testimony. Separately, preliminary discussions about Flynn's prospects for immunity in the FBI investigation also have yielded no agreement.