EDWARDSVILLE, Ill. -- Insurance companies engaged in a conspiracy to defraud motorists by creating a puppet standards-setting agency to make cheaper auto-body repair parts look better than they really were, attorneys claimed in a lawsuit filed Tuesday.

The lawsuit was filed by the attorneys who won a $1.2 billion judgment last month over State Farm's use of after-market parts -- those that were modeled on manufacturer's parts but made without access to factory specifications. A judge ruled that the after-market parts were inferior to those made for automakers.The lawsuit filed Tuesday accuses State Farm and six other insurers -- CNA, Liberty Mutual, Allstate, Geico, Safeco and USAA -- of creating the Certified Automotive Parts Association, or CAPA, to conceal flaws with after-market crash parts.

The creation of CAPA allowed insurance companies to use lower-quality parts while concealing from clients that the after-market parts were used, according to the lawsuit.

CAPA executive director Jack Gillis said the lawsuit was baseless.

Gillis said CAPA has not participated in fraud or conspiracy. The organization is not named in the lawsuit.

Like the State Farm lawsuit, the new lawsuit accuses the insurance companies and their subsidiaries of breach of contract for allegedly failing to restore their customers' cars to their conditions before an accident.

The lawsuit also accuses the companies of consumer fraud and conspiracy. Attorneys are seeking class-action status for the lawsuit.

They claim the companies agreed to promote the use of after-market parts and misrepresent their quality to consumers. In 1988, they decided to form CAPA to "achieve their unlawful ends," according to the suit.

The lawsuit also claims the companies engaged in unfair or deceptive practices in violation of Illinois' consumer fraud law by claiming that after-market parts were of the same quality as original-equipment parts.

Steve Goldstein, a spokesman for the Insurance Information Institute -- the nonprofit communications arm of the insurance industry -- called the accusations "absolutely preposterous."

"The insurance companies have been working hard to try to keep prices down, and one of the ways we can do that is by giving consumers the option of using generic parts," he said.

Many of the insurance companies are facing other lawsuits over use of the parts in the aftermath of the State Farm decision.

In that case, a jury determined State Farm had violated its contract and ordered the company to pay $456 million in damages. The judge added $730 million after finding the company had defrauded consumers by concealing problems with the parts.

State Farm plans to appeal the judgments.