Special Counsel Robert Mueller may have lost his 鈥渟tar witness鈥 after U.S. President Donald Trump suggested that he鈥檚 not opposed to pardoning Paul Manafort. But that doesn鈥檛 mean Mueller鈥檚 investigation is over, according to a lawyer with experience investigating past presidents.

Trump told the New York Post Wednesday that a pardon is 鈥渘ot off the table鈥 for his former campaign chair Paul Manafort, who is currently in jail after being convicted of financial crimes.

鈥淲hy would I take it off the table?鈥 said Trump, who has repeatedly dismissed Mueller鈥檚 investigation as a witch hunt.

Mueller鈥檚 team has accused Manafort of repeatedly lying on a range of subjects related to their probe, which is investigating possible collusion between Trump鈥檚 2016 presidential campaign and Russia.

If Manafort expects a presidential pardon from Trump, there may be little motivation to work with Mueller, according to Paul Rosenzweig, who served as senior counsel in independent investigations into Bill Clinton, including Whitewater and the Monica Lewinsky affair.

鈥淚n some ways he鈥檚 lost his star witness. Manafort cannot be called to testify now because the prosecutor has called him a liar in public. So that makes it an easy shot for the defendants to call him a liar,鈥 Rosenzweig told 麻豆影视.

A rapid-fire series of reports published this week offer new insights into the state of Mueller鈥檚 probe, and how Manafort fits in. The New York Times reported Tuesday that Manafort鈥檚 personal lawyer continually briefed Trump鈥檚 legal team about precisely which evidence Manafort was providing to the Mueller probe.

The same day, The Guardian released a bombshell report alleging that Manafort met with WikiLeaks鈥 Julian Assange around March 2016 鈥 the same month that Manafort joined Trump鈥檚 campaign. It鈥檚 also the same month that Russian hackers began working to hack Hillary Clinton鈥檚 emails.

And then, on Wednesday, CNN reported that Trump told Mueller in writing that he was not told about the 2016 Trump Tower meeting between his son, campaign officials and a Russian lawyer who promised damaging information on Hillary Clinton. Trump also said that former campaign adviser Roger Stone did not tell him about WikiLeaks, according to the report.

Trump鈥檚 comments, if found to be false, could lead to criminal charges.

The WikiLeaks connection?

The developments open up deeper questions about Manafort鈥檚 role, Rosenzweig said.

鈥淭he interesting question is what was he lying about in the debriefing? Before the Guardian report, I might have assumed he was lying about the Trump Tower meeting or about his finances or about the involvement of his wife 鈥 any one of a half dozen things,鈥 he said.

鈥淭aking these two together 鈥 the Guardian report about the Assange-Manafort connection and the report from Mueller that Manafort has been untruthful 鈥 suggests that what may link these two events is precisely Manafort鈥檚 unwillingness to tell the truth about his connections to Julian Assange.鈥

Those sorts of connections are 鈥渉ighly speculative鈥 at this point, Rosenzweig said. But he added that 鈥渢he two coming together certainly suggest a linkage.鈥

鈥淚f Manafort, the Trump campaign manager, is talking to Assange 鈥 then we begin to see possibilities that that connection is really real, and that would actually be collusion,鈥 he said.

If Mueller finds such a link, it would spark a host of questions.

鈥淲hat did he say to Assange? Was he there on behalf of the Trump campaign? It would certainly be the first time that we鈥檝e directly linked any of the Trump core employees in the campaign to Assange and thus to the Russians. And that would be a very significant bombshell if you will,鈥 Rosenzweig said.

Mueller has remained secretive about the investigation, now in its 18th month, and there鈥檚 no way to tell how close he may be to wrapping up. It鈥檚 not uncommon for these sorts of probes to last several years, Rosenzweig said.

鈥淵ou know, 18 months is actually pretty short for these things,鈥 he said.

鈥淚 would say we鈥檙e likely closer to the end than to the beginning. But I don鈥檛 think that we鈥檙e going to see Mueller pack up and go home in February.鈥

Trump has repeatedly trashed Mueller鈥檚 investigation as a 鈥渨itch hunt鈥 motivated by politics. Rosenzweig said that, as more charges pile up, he can see why Trump might be feeling nervous.

鈥淚 understand why the president is afraid of this, and I understand why he feels the need to discredit it. But I don鈥檛 think that any objective assessment of the Mueller investigation would suggest that it鈥檚 a witch hunt.鈥