Social media platforms failed to address online extremism in the lead up to the the riot at the U.S. Capitol, Jan. 6 committee investigators found. But the details didn't make it into the committee's final report because it was "reluctant to dig into the roots of domestic extremism taking hold in the Republican Party beyond former president Donald Trump," The Washington Post reported Tuesday.

A 122-page memo detailing the findings, reviewed by the Post, was omitted from the final report.

"Congressional investigators found evidence that tech platforms — especially Twitter — failed to heed their own employees’ warnings about violent rhetoric on their platforms and bent their rules to avoid penalizing conservatives, particularly then-president Trump, out of fear of reprisals," The Post's report stated. "The draft report details how most platforms did not take 'dramatic' steps to rein in extremist content until after the attack on the Capitol, despite clear red flags across the internet."

Jan. 6 committee staffers wrote in the memo that "alt-tech, fringe, and mainstream platforms were exploited in tandem by right-wing activists to bring American democracy to the brink of ruin."

“These platforms enabled the mobilization of extremists on smaller sites and whipped up conservative grievance on larger, more mainstream ones," the staffers wrote.

But the absence of those findings in the final report showed a missed opportunity to hold tech companies accountable, "even though the platforms had been the subject of intense scrutiny since Trump’s first presidential campaign in 2016," sources speaking to The Post said.

“Given the amount of material they actually ultimately got from the big social media companies, I think it is unfortunate that we didn’t get a better picture of how ‘Stop the Steal’ was organized online, how the materials spread,” said Heidi Beirich, co-founder of the Global Project Against Hate and Extremism nonprofit. “They could have done that for us.”

Read the full report at The Washington Post.