Donald Trump's legal team has been alleged to have blatantly misrepresented the research of a law expert when contending that the former president's impeachment is constitutionally illegal, Reuters said on Tuesday.

Brian Kalt, a professor at Michigan State Law School, released a Twitter thread Monday after Trump's lawyers disclosed their legal brief ahead of their client's second impeachment trial, set to unfurl Tuesday.

Lawyers representing Trump have disputed that the U.S. Constitution only allows for the impeachment of incumbent officials and therefore can't be used against a president who is no longer in office.

In an email to Reuters, Kalt said that his work was "definitely not" correctly detailed in a 78-page report filed by Trump's attorneys.

Kalt is widely considered as the leading expert in constitutional law dealing with the presidency, presidential pardons, impeachment and the 25th Amendment.

According to Kalt, his 2001 133-page law article "The Constitutional Case for the Impeachability of Former Federal Officials" has been cited many times in the brief.

In the document, Trump's attorneys denied he had incited the deadly siege on the U.S. Capitol on Jan. 6, while qestioning the legality of the trial.

"They did not have to be disingenuous and misleading like this," Kalt said, adding that "in several places, they misrepresent what I wrote, quite badly," the report said.

In an interview with the National Review, Kalt said Trump's defense team didn't reach out to him during the drafting of the pre-trial brief, where his name is mentioned 15 times.

"It was never our intention to in any way mislead as to Professor Kalt's position," the Review quoted Trump lawyer David I. Schoen as saying in a statement.

Schoen said Kalt wrote an excellent academic article that laid down all of the evidence that he found on both sides.