A Republican opposition researcher implied a connection to ousted national security adviser Michael Flynn in an effort to obtain Hillary Clinton's emails from Russian hackers, according to a report from The Wall Street Journal.

Long-time GOP operative Peter Smith indicated he was working with Flynn, then an adviser to Donald Trump's presidential campaign, while trying to get emails stolen from the former secretary of state's private server. Emails written by Smith and one of his associates show they at least considered themselves tied to Flynn and his consulting company.

Smith discussed his efforts with the Journal before he died in May 2017 at the age of 81. He said he worked independently and wasn't part of the Trump campaign when he assembled a group of technology experts, lawyers and a Russian-speaking investigator to acquire emails they thought might have been stolen from Clinton. They focused on the 33,000 emails Clinton said were deleted because they were deemed personal and not relevant to her activities as a public servant.

Smith told WSJ they identified five groups of hackers who claimed to have Clinton's emails, two of which were Russian. "We knew the people who had these were probably around the Russian government," he said.

The emails provided by one of the groups couldn't be authenticated, he said.

Smith offered to make introductions to Flynn's son to entice people to join his campaign and gave other signals he was tied to the retired lieutenant general. Smith told one computer expert he was in direct contact with Flynn and his son. In one email, Eric York, a security expert who searched hacker forums on Smith's behalf, said he was "talking to Michael Flynn" about the issue.

Special counsel Robert Mueller is leading the FBI investigation into Russia's meddling in the 2016 election and whether any of Trump's associates colluded to undermine the Clinton campaign.

Flynn has become one of the central figures in speculation surrounding Russia. He resigned from the Trump administration in February after it was revealed that he misled Vice President Mike Pence about his conversations with Russian Ambassador Sergey Kislyak.

Congressional intelligence committees investigating the matter have denied his request for immunity in exchange for freedom to tell his "story." It is not clear whether the FBI has.

Flynn's lawyer, Robert Kelner, did not immediately return request for comment.