A congressional antitrust investigation into Amazon, Apple, Facebook and Google entered a new phase Friday, after lawmakers called on each of the tech giants to turn over a trove of sensitive documents, including top executives’ private communications.

The requests sent by Democrats and Republicans on the House Judiciary Committee ask the companies to share detailed information about their internal operations, including financial data about their products and services, private discussions about potential merger targets and records related to “any prior investigation” they have faced on competition grounds.

Read more at The Washington Post.