Republican Rep. Justin Amash ripped Attorney General William Barr in a lengthy Twitter thread Tuesday, accusing Barr of deliberately misrepresenting the special counsel Robert Mueller's findings in the Russia probe to shield President Donald Trump.

Amash became the first Republican congressman earlier this month to call for Trump's impeachment in the wake of Mueller's report.

He is also the first elected Republican to publicly skewer Barr and his handling of the Russia investigation.

"Barr has so far successfully used his position to sell the president's false narrative to the American people," Amash wrote. "This will continue if those who have read the [Mueller] report do not start pushing back on his misrepresentations and share the truth."

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GOP Rep. Justin Amash skewered Attorney General William Barr in a lengthy Twitter thread on Tuesday, and said Barr "deliberately misrepresented" aspects of the special counsel Robert Mueller's findings in the Russia probe.

Barr's actions, Amash said, "helped further the president's false narrative about the investigation."

Amash made headlines earlier this month when he became the first Republican congressman to call for President Donald Trump's impeachment in the wake of Mueller's findings.

Amash wrote on Twitter at the time that he came to his conclusion "only after having read Mueller's redacted report carefully and completely" and reviewing relevant testimony and materials.

On Tuesday, Amash sharply criticized Barr's handling of Mueller's report, the way it was portrayed to the public, and his subsequent attempts to sugarcoat Mueller's findings in what many saw as an effort to shield Trump.

Amash wrote on Twitter that Barr's March 24 letter summarizing Mueller's findings before the report was released "selectively quotes and summarizes points in Mueller's report in misleading ways."

Read more: 'Fire and Fury' author Michael Wolff claims Mueller drew up a draft indictment against Trump, but Mueller's spokesperson says the documents 'do not exist'

He said Barr quoted Mueller's letter in a way that made it seem as though Mueller could not determine whether Trump's actions amounted to obstruction of justice.

In fact, Amash pointed out, Mueller's report laid out an extensive roadmap of evidence against Trump in the obstruction case and said prosecutors did not make a decision on whether to charge him because of a Justice Department policy that says a sitting president can't be indicted.

Amash also highlighted Mueller's subsequent concerns with the way Barr chose to characterize his findings. The special counsel wrote two letters to the attorney general voicing his frustration, and he asked Barr to release the report's introductions and executive summaries to "alleviate the misunderstandings" that stemmed from Barr's letter.

But "Barr declined," Amash wrote. "He allowed the confusion to fester and only released the materials three weeks later with the full redacted report. In the interim, Barr testified before a House committee and was misleading about his knowledge of Mueller's concerns."

Read more: Trump is said to be telling confidants he 'finally' has 'my attorney general' with William Barr

He was referring to questions Barr was asked at the time about media reports that Mueller's team was frustrated with the way he characterized their findings. Amash wrote that Barr "absurdly" denied knowing anything about it, despite having received two letters from Mueller on the topic days before the hearing.

Amash, who has a law degree from the University of Michigan, also lambasted the attorney general for falsely claiming that Mueller found "no collusion" between Trump associates and Russians.

Amash echoed the majority of legal experts when he emphasized that there's a significant difference between not having enough evidence to charge someone with a crime, and not having evidence that someone engaged in wrongful conduct.

"In truth, Mueller's report describes concerning contacts between members of Trump's campaign and people in or connected to the Russian government," Amash wrote.

For that reason, he added, "it's wrong to suggest that the fact that Mueller did not choose to indict anyone for this means there wasn't a basis to investigate whether it amounted to a crime or 'collusion'…"

Amash also said Barr was wrong when he said the White House "fully cooperated" with the investigation, given that Mueller unsuccessfully sought an interview with Trump for over a year. Trump's son, Donald Trump Jr., also refused to testify before prosecutors.

"Barr has so far successfully used his position to sell the president's false narrative to the American people," Amash concluded. "This will continue if those who have read the report do not start pushing back on his misrepresentations and share the truth."