(Reuters) - The timing of the release of Special Counsel Robert Mueller’s report on Russia’s role in the 2016 U.S. election is a major topic of discussion in Washington, with the disclosure of the findings expected to be a seismic event in American politics.

FILE PHOTO: Robert Mueller, as FBI director, testifies before the U.S. Senate Judiciary Committee on Capitol Hill in Washington. Sept. 16, 2009. REUTERS/Yuri Gripas/File Photo

Mueller himself has been silent throughout the probe, but his team has provided clues that prosecutors are still working on key issues, an indication he may not be ready to submit the report to Attorney General William Barr imminently.

The special counsel since May 2017 has been investigating whether Trump’s campaign conspired with Russia and whether the Republican president has unlawfully sought to obstruct the probe. Trump has denied collusion and obstruction. Russia has denied election interference.

Representatives of key congressional committees involved in their own Trump-related probes have said they have received no guidance from Mueller’s office regarding his investigation’s progress or future plans.

Here is an explanation of some of the ongoing areas of inquiry for the special counsel.

MANAFORT AND KILIMNIK

At the March 7 sentencing hearing in Virginia for Trump’s former campaign chairman Paul Manafort, prosecutor Greg Andres said a filing by the special counsel in a separate case against Manafort in Washington was partially sealed due to a “continuing investigation.” Manafort is due to be sentenced in the Washington case on Wednesday.

The continuing investigation cited by Andres, a member of Mueller’s team, related to Manafort’s interactions with Konstantin Kilimnik, his former business associate who the special counsel has said has ties to Russian intelligence. Manafort and Kilimnik, a Russian, worked together for more than a decade as consultants for pro-Kremlin politicians in Ukraine.

A January court filing showed Manafort was accused by prosecutors of lying about sharing with Kilimnik in 2016 polling data related to Trump’s campaign. The New York Times also reported that Manafort asked that Kilimnik pass the data to two Ukrainian oligarchs, Serhiy Lyovochkin and Rinat Akhmetov, who had financed pro-Russian Ukrainian political parties that had paid Manafort millions of dollars as a political consultant.

At issue is why Manafort passed along the polling data. Prosecutors also are examining Manafort’s discussions with Kilimnik about a policy proposal aimed at resolving the conflict in Ukraine in a way favorable to the Kremlin.

Andrew Weissmann, another Mueller prosecutor, said at a Feb. 4 hearing that Manafort’s alleged lies about interactions with Kilimnik were significant because they related to “what we think the motive here is.” Weissmann added, “This goes, I think, very much to the heart of what the Special Counsel’s office is investigating,” a comment that suggested Mueller’s team was still digging into the matter.

This line of inquiry potentially could lead to conclusions by Mueller about Russian links to the Trump campaign.

ROGER STONE AND WIKILEAKS

Mueller’s team said in a Feb. 15 court filing it had evidence of some communication between longtime Trump advisor Roger Stone and the WikiLeaks website related to its release of Democratic Party emails that prosecutors have said were hacked by Russians. The special counsel has said the emails were released to harm Trump’s Democratic opponent Hillary Clinton.

The special counsel’s disclosure was aimed at showing a link between the case against Stone, indicted in January for lying about his communications concerning WikiLeaks, and a separate case against 12 Russian military intelligence officers indicted in July 2018 for hacking Democratic emails.

Stone, who has pleaded not guilty, is set to go to trial later this year in a case that could answer a central question of the Mueller probe: whether there was coordination between WikiLeaks and anyone close to Trump.

There are additional signs Mueller is still gathering evidence on Stone. A lawyer for Andrew Miller, a Stone associate who on Feb. 26 lost an appeal aimed at staving off a grand jury appearance, told Reuters Mueller still wants his client to testify.

Jerome Corsi, another Stone associate, told Reuters he no longer believes he will be indicted by Mueller for allegedly lying about his interactions with Stone but has not yet been told how he will figure in the investigation. Corsi said he turned down a deal to plead guilty in the case and is he cooperating with Mueller.

Michael Cohen, Trump’s former personal lawyer and self-described “fixer,” told a congressional panel on Feb. 27 that he overheard a telephone call in which Stone relayed to Trump that WikiLeaks founder Julian Assange had given him advance knowledge about an impending release by the website of stolen Clinton emails. WikiLeaks has denied any substantive contacts with Stone.

OBSTRUCTION OF JUSTICE INQUIRY

Of all the avenues of inquiry, perhaps the least is known about Mueller’s investigation into whether Trump obstructed justice by trying to impede the Russia inquiry. There have been no indictments or court action related to this issue.

A pivotal incident was Trump’s May 2017 firing of FBI Director James Comey, an act some legal experts have said could be charged as obstruction of justice especially because Trump days later told NBC News he was thinking about “this Russia thing” when he made the decision. The FBI was leading the Russia investigation at the time. The Justice Department’s No. 2 official, Rod Rosenstein, then appointed Mueller to take over the probe.

Legal experts have pointed to more than a dozen other incidents that could come under Mueller’s scrutiny. These include: Comey’s account of Trump in February 2017 asking him to drop a probe into then-national security adviser Michael Flynn’s ties to Russia; a January 2018 New York Times report that Trump ordered the firing of Mueller but backed down after then-White House Counsel Don McGahn threatened to quit; and the dangling of possible presidential pardons to Manafort and others.

Mueller also could look at Trump’s relentless public attacks seeking to discredit the investigation. Trump has described Mueller’s investigation as a “witch hunt,” has accused the special counsel of conflicts of interest and has called his prosecutors “thugs.” Trump also repeatedly criticized Attorney General Jeff Sessions for recusing himself from overseeing the probe and eventually ousted him in November 2018.

FUNDING FOR SPECIAL COUNSEL

Funding is in place for the special counsel investigation through the end of the current fiscal year on Sept. 30, three U.S. officials said on Monday, an indication the probe has money to keep it going for months if necessary. Justice Department documents show that Mueller’s office reported spending around $9 million during the 2018 fiscal year that ended last Sept. 30. No figures are available for fiscal 2019.