FILE - The social media application, Facebook is displayed on Apple's App Store, July 30, 2019. Facebook is launching a long-promised tool that lets users block the social network from gathering information about them on outside websites and apps.
FILE - The social media application, Facebook is displayed on Apple's App Store, July 30, 2019. Facebook is launching a long-promised tool that lets users block the social network from gathering information about them on outside websites and apps.

WASHINGTON - The U.S. Justice Department will open an antitrust investigation of Facebook Inc., a source familiar with the matter said Wednesday.

It will mark the fourth recent investigation of the social media company, which also faces probes by the Federal Trade Commission, a group of state attorneys general led by New York and the House of Representatives Judiciary Committee.

Reuters and others reported in June the agencies had divided up the companies being investigated, with Justice taking Alphabet Inc.'s Google and Apple Inc., while the FTC looked at Facebook and Amazon.com Inc.

The Justice Department later said it was opening a probe of online platforms without saying which ones. This led some industry observers to question whether the two federal investigations would overlap.

Lawmakers, in particular Sen. Mike Lee, chair of the Senate Judiciary Committee's antitrust panel, criticized the appearance of an overlap in a hearing last week.

The agencies generally have a practice of meeting to decide who will investigate which matter but the FTC cannot probe certain matters, for example price-fixing.