Google shares are sliding notably after Bloomberg reports that US state attorneys general are taking their first steps toward a Google Probe.

Bloomberg reports that an emerging leader among the state officials is Nebraska’s attorney general, Doug Peterson. He attended the meeting last fall, and discussed his suspicions about tech companies with the Omaha World-Herald. Peterson told the newspaper a story about a family he’d heard from who were discussing a particular consumer product at dinner one night, only to start receiving advertisements for the product on their phones the following morning.

“And they’re going, okay, the linkage here is too obvious,” Peterson said. “Who’s listening to what I’m saying?”

In an interview with Bloomberg Businessweek earlier this month, Peterson said he was “carrying the ball” for attorneys general concerned about issues of privacy and market power, but he also suggested the work was in early stages.

“The topic is deep and complex, and so we’re learning,” he says. When asked about the group investigating Google, he declined to comment further.

People familiar with the state’s interest in the tech industry say that impatience with federal action may push the group toward action.

And the reaction in Google shares is clear..

Antitrust experts say the chances of a serious lawsuit against a technology company seem to be increasing. But some of them also acknowledge that they’ve been anticipating the next big legal battle ever since the FTC ended its antitrust investigation into Google in 2013. “A platform is going to be a defendant in a big case,” says Chris Sager, a law professor at Cleveland State University. “It has felt that way for five years.”