President Donald Trump's pardons of those convicted in the Jan. 6, 2021, attack on the U.S. Capitol and the rhetoric of retribution from some of those released this week is raising deep concern among attorneys, former federal investigators and experts who follow extremism.

Nearly four years after a mob stormed the U.S. Capitol, political violence remains a persistent threat heading into another presidential election.

Social media platforms like Facebook, TikTok and Twitter say they're taking steps to prevent the spread of misinformation about voting and elections ahead of next month's midterms.