Senior executives from Facebook, Twitter, and Google testified on Tuesday before a Senate judiciary subcommittee. On Wednesday they will appear before Senate and House intelligence committees investigating Russian interference in the 2016 U.S. election. The House intelligence committee is expected to publicly release much-anticipated copies of Facebook ads purchased by the Kremlin-based Internet Research Agency. According to testimony by the companies on Tuesday, Russian agents spread inflammatory posts that reached 126 million Facebook users, published more than 1.4 million messages on Twitter and uploaded more than 1,000 videos to Google’s YouTube service.