A coalition of 38 attorneys general led by Colorado and Nebraska is suing Google for muscling competitors out of the search market, marking one of the most serious threats to Google's business model yet.

The lawsuit, which was filed in federal court in Washington, D.C., will likely be consolidated with the DOJ's narrower case against Google's search dominance.

"Our economy is more concentrated than ever, and consumers are squeezed when they are deprived of choices in valued products and services," said Colorado Attorney General Phil Weiser in a statement. "Google's anticompetitive actions have protected its general search monopolies and excluded rivals, depriving consumers of the benefits of competitive choices, forestalling innovation, and undermining new entry or expansion."

"This lawsuit seeks to restore competition," he said.

The states' complaint accuses Google of engaging in a multi-pronged effort to maintain its monopoly over search, focusing specifically on allegations that it manipulated search results to preference its own products.

It's the third major antitrust challenge against Google in recent weeks, and comes a day after a coalition of ten state attorneys general sued Google for maintaining a monopoly over the ad tech market.