A lawyer who went to Princeton with Robert Mueller has described his 'shady' tactics and eagerness to prosecute where no crimes exist.

Harvey Silverglate is a prominent Massachusetts defense attorney. His and Mueller's careers ascended simultaneously, with Mueller rising through the ranks of public service while Silverglate worked privately as a criminal defense attorney.

In an article for WGBH News that was published on Saturday, Silverglate recalled two occasions during their 30 year-careers which have prompted him to be suspicious of Mueller, who graduated two years after he did.

Each indicate his 'zeal' to find wrongdoing, a trait which he says may result in wrongful charges being brought against Trump's campaign team over their alleged ties to Russian officials.

'My experience has taught me to approach whatever he does in the Trump investigation with a requisite degree of skepticism or, at the very least, extreme caution.

'Special counsel Mueller’s background indicates zealousness that we might expect in the Grand Inquisitor, not the choirboy.

'If Mueller claims that Trump or members of his entourage committed crimes, it doesn’t mean that it’s necessarily so.

'We should take Mueller and his prosecutorial team with a grain of salt,' Silverglate said.

Defense attorney Harvey Silverglate (left) has said Robert Mueller's 'zealousness' to prosecute means he sometimes reverted to 'shady' tactics

Their first run-in was in the 1980s when he claims Mueller, the then acting United States Attorney in Boston, tried to set him up for perjury.

'I was defense counsel in a federal criminal case in which a rather odd fellow contacted me to tell me that he had information that could assist my client.

'He asked to see me, and I agreed to meet,' Silverglate recalled.

He claims the 'odd fellow', who he did not name, then offered to sign an affidavit which would exonerate Silverglate's client but, as he was about to put pen to paper, admitted that he was lying.

Silverglate then realized the man was wearing a wire and had been recording their conversation.

Years later, he asked Mueller, whose office was on the opposite side of the case, about it and he claims he admitted orchestrating the sting.

'Mueller, half-apologetically, told me that he never really thought that I would suborn perjury, but that he had a duty to pursue the lead given to him,' Silverglate said.

Their professional paths crossed again in 1990 when Mueller was the head of the criminal division of the Department of Justice.

Silverglate had been appointed as one of the attorneys for Dr. Jeffrey McDonald, a notorious Green Beret doctor who was convicted of murdering his pregnant wife and their two children years earlier in 1979.

Silverglate said in the 1990s, when he was the head of the Department of Justice's criminal division, Mueller ignored allegations of prosecutorial misconduct within the FBI on a murder case. Mueller is pictured in 1991 at a press conference related to the 1988 bombing of Pan Am Flight 103 over Lockerbie, Scotland

In 1990, Silverglate (left) was brought on to the appeal of Dr. Jeffrey McDonald, a Green Beret doctor who was convicted of murdering his wife and children in 1979 but who protested his innocence and claimed he had been framed

In 1990, in an effort to appeal his conviction, he hired Silverglate to present evidence he had gathered which he claimed proved he was framed by the FBI.

When Silverglate called a meeting with Mueller to discuss the evidence though, he claims he immediately vetoed any talk of misconduct on the part of the bureau or its investigators and essentially ignored the evidence.

'Mueller walked into the room, went to the head of the table, and opened the meeting with this admonition, reconstructed from my vivid and chilling memory: “Gentlemen: Criticism of the Bureau is a non-starter.”

'Another lawyer attendee of the meeting remembered Mueller’s words slightly differently: “Prosecutorial misconduct is a non-starter.”

Silverglate said Mueller, who impaneled a grand jury in August, should be taken with a 'grain of salt' and that any charges he may choose to bring against any of Trump's team may not be entirely legitimate

'Either version makes clear Mueller’s intent – he did not want to hear evidence that either the prosecutors or the FBI agents on the case misbehaved and framed an innocent man,' Silverglate said.

The two instances give Silverglate reason to question the integrity of any investigation Mueller is put in charge of.

Mueller declined to comment on the claims via a personal spokesman on Saturday afternoon.

His investigation is ongoing and coincides with separate probes by a Senate Intelligence Committee and a Judiciary Committee.

So far, the president's son-in-law, his eldest son and Trump loyalist Paul Manafort have all faced questions over their ties to Russian officials during the campaign.

In August, Mueller impaneled a Washington grand jury to examine documents relating to the case.