(CBS) By CBS News Investigative Unit Contributor Myron Levin

A former attorney for Toyota has accused the automaker of illegally withholding evidence in hundreds of rollover death and injury cases, in a "ruthless conspiracy" to keep evidence "of its vehicles' structural shortcomings from becoming known."

The explosive allegations are contained in a federal racketeering suit filed in Los Angeles by Dimitrios P. Biller, former managing counsel for Toyota Motor Sales, USA, Inc., who claims his complaints about the company's legal misconduct cost him his job.

Toyota, which is second to General Motors in car and truck sales in the U.S., called Biller's charges "inaccurate and misleading," in a statement issued late Friday to CBS News. "Toyota takes its legal obligations seriously and works to uphold the highest professional and ethical standards," the company said.

Company lawyers have not filed an answer to Biller's lawsuit, but have brought a motion to seal the complaint, claiming it is "rife with privileged and confidential information" that Biller, as a former Toyota lawyer, has no right to divulge.

A hearing on the motion has been set for September 14.

Biller, who did not return phone calls, worked for Toyota Motor Sales, based in Torrance, Calif., from 2003 to 2007. He was involved in defending rollover lawsuits that blamed injuries and deaths on instability and weak roofs of the company's SUVs and pickups. Along with Toyota Motor Sales and Japanese parent Toyota Motor Corp., his suit names five senior executives and lawyers of Motor Sales. The case was filed July 24 in U.S. District Court in Los Angeles, but has not been publicized until now.

Biller's 75-page complaint says that when he came to Toyota after nearly 15 years in private practice, he was "surprised and alarmed" to discover that the company was not producing e-mails and other electronically stored information to plaintiffs as he said was required. According to the lawsuit, Biller repeatedly complained to supervisors that the company was illegally withholding evidence.

The lawsuit further states that the resulting conflicts ultimately caused Biller to suffer a mental breakdown and led to his forced resignation in September 2007. He left with a $3.7 million severance agreement, court records show.

Read the lawsuit Biller v. Toyota (pdf)

The complaint charges that in a pair of lawsuits in Colorado and Texas, Toyota failed to fully disclose electronic data (such as e-mails) in defiance of court orders to do so. It states that when Biller learned of the company's failure to produce design and test data from an engineering subsidiary, he attempted to collect and preserve the information.

Despite these efforts, the engineering unit "was allowed to destroy relevant information and documents that should have been produced in, approximately, over 300 rollover accidents involving roof crush issues," the lawsuit claims.

It further charges that Toyota regularly, and improperly, withheld records on design and testing of vehicle roofs. For example, it says that Toyota never produced a document showing that the company's internal standard for roof strength was tougher than the federal requirement. Toyota engineers and witnesses repeatedly testified that the internal standard did not exist, the lawsuit says, adding that there are vehicles on the road today that do not meet the standard.

Word of the case has electrified the plaintiffs' bar, where some lawyers involved in vehicle cases have long voiced suspicions about foreign automakers withholding evidence.

Stuart Ollanik of the Denver firm of Gilbert, Ollanik and Komyatte, which has settled dozens of Toyota rollover cases, said he was "blown away" by the allegations, and wondered aloud if his cases "were resolved based on honest information or not." Ollanik said he had no "independent information about whether the things alleged in Mr. Biller's lawsuit are true, but if they are they're extremely serious."

With grim memories of Toyota's May 2004 courtroom victory over his quadriplegic client in a Toyota 4Runner rollover case, San Jose lawyer James McManis said he, too, was riveted by the charges. In the 4Runner case, everything with Toyota "was a big fight - and I mean everything - but I never suspected they were behaving dishonestly or concealing or withholding evidence," McManis said. "So I'm very interested in knowing whether we got all the discovery we should have got."

Biller is no stranger to litigation, and even before the lawsuit his battles with Toyota were exceedingly bitter. After leaving Toyota in 2007, he set up a consulting firm to provide attorneys with continuing education on such subjects as trial preparation and discovery of electronic records. But Toyota claimed that information provided on the firm's Web site and in class sessions violated the confidentiality clause of his severance agreement. Toyota obtained a restraining order against Biller, court records show.

Biller's lawsuit also notes that he has a separate wrongful termination claim against the Los Angeles County District Attorney's office, where he briefly worked from May to August 2008, as an assistant district attorney. Biller said he was fired over what he described as a dispute over sheriff's deputies failing to show up for hearings or failing to bring evidence.

In its statement Friday, Toyota said it was "disappointed" that Biller has attempted "to avoid what we believe are his obligations as an attorney formerly employed by Toyota. In our view, Mr. Biller has repeatedly breached his ethical and professional obligations, both as an attorney and in his commitments to us, by violating attorney-client privilege."

In the lawsuit, however, lawyers for Biller described Toyota's effort to silence him as "illegal and against public policy in that it is intended to conceal information from plaintiffs and obstruct justice."