Ongoing federal and state probes in New York could pose “an even greater threat than the Russia probe”, experts said, after the special counsel cleared the president’s campaign team of colluding with the Kremlin to interfere in the 2016 election.
Federal prosecutors in Manhattan are pursuing at least two known criminal inquiries, one focused on possible corruption in Mr Trump’s inaugural committee and the other on the hush-money scandal that has left his former lawyer, Michael Cohen, facing prison for campaign finance violations.
The president also faces scrutiny from New York’s attorney general, who is investigating Mr Cohen’s claims that the president exaggerated his wealth when seeking loans for property projects and in a failed bid to buy the NFL’s Buffalo Bills.
State regulators, meanwhile, are looking into whether Mr Trump gave false information to insurance companies.
Mr Cohen told congress in testimony last month he is in “constant contact” with prosecutors over the ongoing investigations.
Patrick Cotter, a former federal prosecutor in the Southern District of New York, said the probes were “very real and very significant”.
“If you’re Trump, this has got to feel, in some ways, like an even greater threat than the Russia probe,” he added.
Political observers have speculated that Mr Cohen, who is scheduled to report to prison to begin a three-year sentence May, might secretly be providing investigators with additional information.
The president's former lawyer and longtime fixer has said Mr Trump ordered and personally reimbursed six-figure payments to adult film actress and former Playboy model Karen McDougal to suppress affair allegations during the election campaign.
Mr Cohen also stoked speculation when he told congress he was aware of other "wrongdoing" involving Trump but could not talk about it because it was "part of the investigation that's currently being looked at by the Southern District of New York".
"If you've got Michael Cohen, the president's former lawyer, as a tour guide, that means you could go anywhere," former New Jersey governor Chris Christie later told MSNBC.
Mr Trump denies wrongdoing and has dismissed the New York investigations as politically motivated harassment, a claim he and his supporters are likely to return to in the wake of Mr Mueller’s findings.
Attorney general William Barr said in letter to congress on Sunday that the special counsel’s two-year investigation did not find the president’s 2016 campaign “conspired or coordinated” with Russia to influence the election. The probe did not come to a definitive answer on whether Mr Trump obstructed justice.
"While this report does not conclude that the president committed a crime, it also does not exonerate him," Mr Mueller noted, according to the attorney general.