(Bloomberg) -- More than half of state attorneys general are planning to open an antitrust investigation of Alphabet Inc.’s Google as soon as next week, according to two people familiar with the matter.

Multiple states are planning to announce the coordinated probe on Sept. 9, said three people, who asked not to be identified discussing sensitive deliberations. The states are also expected to stage the announcement in front of the U.S. Supreme Court in Washington, one of the people said. The plans could change.

U.S. antitrust enforcers are already investigating the search giant, which is also a major player in online ads and mobile operating systems. The Department of Justice is scrutinizing the latter two operations, Bloomberg has reported. The company has faced antitrust investigations in Europe as well. Although states with Democratic attorneys general have recently led the charge on tech and telecom issues, the group scrutinizing Google is led by Texas Attorney General Ken Paxton, a Republican, one of the people said.

In July, Paxton said that a bipartisan group of eight of his counterparts spoke with Attorney General William Barr about “the real concerns consumers across the country have with big tech companies stifling competition on the internet” and that the state officials were “considering a range of possible antitrust actions against such companies.”

The Justice Department will not be involved in the announcement, one of the people said. The department declined to comment.

The Washington Post previously reported the state investigation. It was not immediately clear what the probe would focus on or which states would participate.

A group of state attorneys general said in June at an enforcement workshop hosted by the Federal Trade Commission that they are examining a wide range of practices, including data collection, digital advertising and innovation, among large tech companies.

Google spokesman Jose Castaneda said the company continues “to work constructively with regulators, including attorneys general, in answering questions about our business and the dynamic technology sector.”

States often team up to investigate and sue companies over conduct that’s national in scope. Different groups of states sued Standard & Poor’s over faulty ratings on mortgage bonds in 2013 and foreclosure practices by banks in 2012. The states also negotiated a sweeping settlement with the tobacco industry in the 1990s.

(Updates with additional details from third paragraph.)

--With assistance from Erik Larson and David McLaughlin.