This latest suit, brought in federal district court in San Jose, Calif., comes less than one week after attorney Hal Levitte filed a similar case.

In the new lawsuit, online retailer RK West, which operates the online store Malibu Wholesale, alleges it purchased ads Google without realizing they would appear on parked domains. Parked domains typically have no content other than ads. RK West alleges that many of the clicks generated by parked domains are "invalid."

The company said in its lawsuit that it had been charged for clicks from parked domains "that had little relation to its business."

"Despite indication that some of the clicks from parked domains were invalid, Google failed to disclose to the plaintiff specific domain names in which these ads were clicked on, making detection of invalid clicks difficult and even worse concealing any evidence of invalid clicks," the lawsuit alleges. RK West eventually went through its server logs and discovered the source of the clicks, said Alfredo Torrijos, one of the company's attorneys.

RK West does not define "invalid" in the complaint, but Torrijos said the company took the position that clicks made by users who don't have a genuine interest in making a purchase are invalid.

The company has alleged fraudulent concealment, unjust enrichment and a violation of California's business code, and is seeking class-action status.

RK West's lead lawyer, Brian Kabateck of Kabateck Brown Kellner, has a history of bringing click fraud lawsuits, having sued Google, Yahoo and IAC. His law firm settled with Yahoo and joined in a $90 million settlement with Google.

In April he sued Google on behalf of David Almeida, who alleged that Google tricked him into paying for AdSense ads on the company's publisher network, when he only wanted his ads to appear on search results pages.