The CEOs for four of the biggest U.S. technology companies will appear together for questioning in front of the House Judiciary Committee this month as it investigates online competition.

Rep. Jerry Nadler of New York, the chairman of the Democrat-led committee, and Rep. David Cicilline of Rhode Island, the Democratic leader of the House Judiciary Antitrust Subcommittee, announced on Monday that Amazon CEO Jeff Bezos, Apple CEO Tim Cook, Facebook CEO Mark Zuckerberg, and Google CEO Sundar Pichai will all testify “as part of the Committee’s ongoing investigation of competition in the digital marketplace.”