A bipartisan group of attorneys general from across the country announced an antitrust investigation of Google (GOOG), saying they want to know if company poses a threat to consumers and competition.

Texas Attorney General Ken Paxton announced the action, involving attorneys general in 48 states, the District of Columbia and Puerto Rico, on the steps of the U.S. Supreme Court, saying Google “dominates all aspects of advertising on the internet and searching on the internet.” Only California and Alabama are not participating.

“Facts will lead where the facts will lead,” Paxton said, adding that the initial investigation is about digital advertising.

Sen. Josh Hawley tweeted it’s “going to be a very bad day” for Google.

“I’m next to friends of mine who I vehemently disagree with,” Karl Racine, attorney general for the District of Columbia, said during the press conference. “But we are acting as one today.”

The announcement is just the latest in a series of headaches for Google and its tech peers. The Department of Justice and the Federal Trade Commission are conducting their own inquiries. Justice asked Google for its first cache of documents related to past investigations at the end of August, Google confirmed in a securities filing last week, pledging to comply with all investigations.

The FTC previously has looked for antitrust violations related to Google’s search and advertising businesses but ended the probe without taking major action in 2013. Investigations also have been announced by the House Judiciary Committee and the antitrust subcommittee of the Senate Judiciary Committee.

"We have always worked constructively with regulators and we will continue to do so," Kent Walker, senior vice president of global affairs, wrote in a blog post Friday.

"This adds a whole different level of complexity for both Facebook and Google to deal with because they're dealing with potentially many different investigations, not all of which may be coordinated," Robert Litan, who was principal deputy assistant attorney general in the DOJ's antitrust division during the Clinton administration, told Politico. "All I know is I'm sure this is a major headache for the general counsels of both of these companies."

Investigators want to hear from Google employees about evidence of wrongdoing.

“This is not anti-tech,” Republican Utah Attorney General Sean Reyes said. “To the opposite, this is actually for the benefit of the tech ecosystem, to help level the playing field.”

The European Union fined Google $9 billion in March for harming competition and consumers, accusing Google of prioritizing its own offering over rivals in search results.

New York Attorney General Letitia James announced an investigation of Facebook Friday to determine whether the company mishandles personal information and violates competition laws.