Don Harrison,Google’s President of Global Partnerships and Corporate Development, will appear on Sept. 15,  before Congress to answer questions by the United States Senate’s antitrust panel, which will investigate Google’s advertising business, focusing on the growing concerns about the existence of an anti-competitive market in the industry, promoted by Google. At the same time, the Justice Department is preparing to file a lawsuit against the technology giant in the coming weeks.

The Senate hearing will focus on Google’s effect on competitors in the digital advertising market, where the company gets most of its revenue. The panel will also be looking for a response from the company based on the assumption that it misused its domain in online advertising, to generate extraordinary profits.

According to Reuters, Sen. Mike Lee (R-Utah), chairman of the Senate Judiciary Committee’s antitrust panel, is also likely to press the Google executive about the lack of transparency in pricing advertising services, following constant complaints from critics.

Based on comments from a source close to the panel, Lee is expected to express concern that Google may have violated U.S. antitrust law.

Harrison will represent Google before the panel. Harrison took over as Google’s director of corporate development in 2012, and since then he has overseen advertising partnerships with other companies.

Harrison will surely argue that the advertising technology system is crowded, competitive, and that advertising technology rates have fallen. While Amazon.com Inc. and Facebook Inc. are among Google’s powerful rivals.

Harrison is also expected to argue that advertising, as they use it, is critical to support free websites, including the popular Google search engine.

As The Washington Post recalled, Google is not the only company being investigated by the Senate antitrust committee. Three more Big Tech companies were questioned in congressional hearings in July: Facebook for its acquisition of smaller companies such as Instagram, Apple for its control of the App Store, and Amazon for the way it collects data from third-party vendors on its site.

For years critical analysts and small competitors have claimed U.S. laws have failed to control large technologies, which would allow companies to accumulate more and more power. 

The antitrust commission promoted by the Republicans would make real progress in bringing about change, and Google would become the first target of what could be a turning point in antitrust regulation in the United States. 

At the same time, according to Fox Business, the Justice Department has been conducting an in-depth investigation of Google’s behavior in the advertising market and in its search system, under the magnifying glass of the antitrust law in force in the United States.

The department is focusing on allegations that Google violates antitrust laws by favoring its own business units in searches, for example, in video search results it prioritizes YouTube instead of presenting neutral results.

According to sources consulted by Fox Business, the lawsuit will be filed in the coming weeks.