Lawmakers met with the chief executives of the tech industry’s four most powerful players, Amazon, Apple, Facebook, and Google. Each company is under antitrust scrutiny for different reasons, but the committee used this week’s hearing to point out similarities between all four.

Lawmakers have been engaged in a sweeping antitrust investigation into the tech sector since last June. Lawmakers have heard hundreds of hours of testimony and obtained over one million documents throughout their investigation. The process made it difficult for CEOs like Facebook’s Mark Zuckerberg and Amazon’s Jeff Bezos to evade uncomfortable lines of questioning.

The committee found problemsome patterns of behavior that all four firms exhibit. This includes how each company controls distribution, surveils competitors, and abuses their control over tech.

Rep. DAVID cicilline, the chairman of the House Judiciary Committee’s subcommittee on antitrust, said’we have observed common patterns and competition problems over the course of our investigation’.

Apple and Amazon both hold tremendous power over who gets to put up apps and sell products. Rep. Val Butler demings asked Apple’s CEO Tim Cook about its app store rules.

Google is accused of keeping a watchful eye on competitors in search. cicilline cited emails obtained through the investigation between Google employees. Google allegedly threatened to delist its reviews if the giant could n’t feed them into its own products.

Rep. Lucy mcbath pointed out Amazon’s ability to’systematically block’ sellers from selling products in specific categories. Amazon was the committee’s primary example of this behavior.

Third-Party sellers in aggregate are doing extremely well on Amazon.’I do not think that’s systematically what’s going on,’ said Bezos.