LOS ANGELES (AP) – Barbie doll maker Mattel Inc. claims rival MGA Entertainment Inc. stole its concept for the lucrative Bratz doll line and other trade secrets by luring away Mattel employees who fed confidential information to their new employer.

The claims were outlined in a revised complaint filed Monday in U.S. District Court in Riverside.

El Segundo-based Mattel filed the original lawsuit in 2004 against one of its former doll designers, Carter Bryant, accusing him of wrongfully selling his concepts for Bratz to privately held MGA.

In the expanded complaint, which must be approved by the court, Mattel extends allegations of intellectual property theft to MGA itself, accusing the company of stealing the Bratz doll line designs and then continuing to pilfer Mattel’s confidential and proprietary information to fuel its growth.

“Emboldened by the success of its illegal conduct, MGA has repeated – even expanded – its pattern of theft on numerous occasions,” the lawsuit claims.

MGA CEO Isaac Larian, who is named as a defendant in the amended complaint, called Mattel’s claims “a bunch of nonsense.”

“This lawsuit proves that Mattel is desperate,” he said. “They wish they owned Bratz. They don’t and they know it. The last time I checked, it was not illegal for people to leave one company to go to a better company for a better job.”

Mattel, the world’s largest toy maker, has seen sales of its Barbie dolls suffer from competition by the edgier, urban-styled Bratz line, which MGA launched in 2001.

Mattel contends MGA hired away three key Mattel employees in Mexico who “stole virtually every category of Mattel’s sensitive and trade secret business plans and information” for markets in Mexican and elsewhere.

MGA employed the same strategy to lure Mattel workers in Canada, according to the lawsuit.

Mattel issued a brief statement acknowledging it was seeking permission to expand the lawsuit but declined further comment.

Bryant has said Mattel wants to co-opt the Bratz line, which he claims he did not take beyond the idea stage until after he left the company.

Last year, MGA sued Mattel, claiming the company was using its clout with retailers to stifle competition. MGA also accused Mattel of altering the design of its own “My Scene” dolls to more closely resemble the Bratz line.

That lawsuit is pending.