For Toyota, Karl Stopschinski is the company's crown jewel in a federal trial in Minneapolis, a savvy, meticulous engineer who has conducted an elaborate investigation and road tests to prove that its 1996 Camry is not responsible for three deaths and multiple injuries in a tragic car crash in St. Paul nearly nine years ago.

But for the lawyers of the families of the deceased, the injured and the driver of the Camry, Stopschinski is a one-sided, high-paid hired gun who will do whatever it takes to convince a jury that the Camry had no defects, no matter how compelling the evidence otherwise.

He was closely cross-examined on Thursday and Friday by the lead attorney for the driver, Koua Fong Lee, and the families, and at times it felt like high theater.

Bob Hilliard, a soft-spoken Texas lawyer with a national reputation, poked, probed and suggested that Stopschinski failed to conduct tests that would prove that Lee was not at fault when his Camry crashed into the left rear end of a 1995 Oldsmobile Ciera on June 10, 2006.

"What would a working definition of bias be for you?" was the first question Hilliard asked Stopschinski.

"I'd probably say leaning one way or another," said Stopschinski.

"OK, I'll accept that," said Hilliard.

"Showing of a financial interest is also another way to help expose bias if any bias exists?" Hilliard asked Stopschinski.

"It could be," said Stopschinski.

Hilliard followed with a series of questions in which he underscored that Stopschinski and Carr Engineering Inc., the Houston company that employs him, have billed Toyota $34,049,000 from 2003 to 2013 and that they have billed about $300 million to a string of other auto companies, including General Motors, Chrysler, Nissan and Jaguar.

Stopschinski testified Friday that for this case, Toyota had paid him fees and expenses of $747,000 through June 30, 2013, although he has not provided dollar amounts for the time that has since elapsed. Hilliard said Thursday that he calculated he'd been paid $1.4 million.

Asked by the Star Tribune during a recess how much his side had paid the two experts who testified on behalf of Lee and the families, Hilliard said $65,000 to $70,000.

Before Hilliard dug into Toyota's key witness, however, Stopschinski scored some points himself, testifying at length on tests he conducted that he said proved that Lee accidentally stepped on the gas pedal rather than the brakes at the top of the Snelling Avenue exit off eastbound Interstate 94, causing the crash.

Stopschinski was led through his testimony by Toyota's attorney, David Graves, chairman and managing partner of the Minneapolis firm Bowman and Brooke who has long represented Toyota and other auto manufacturers.

Stopschinski illustrated his position with videos of driving tests using another 1996 Camry on the Snelling ramp. He also testified about tests performed at the company's Houston headquarters and on a test track in College Station, Texas. He introduced video simulations of how he believes the collision occurred, how the engine parts, accelerator and brakes reacted, and why no defective parts or engineering were responsible for the crash.

In tests on the track, Carr engineers pressed the accelerator to the floor, then applied the brakes. Invariably, they found that the Camry slowed down, which they said undermined Lee's claims that although he pumped the brakes, the car seemed to speed up.

Asked by Graves what would happen if the accelerator became stuck and Lee hit the brake pedal, Stopschinski said, "The vehicle would not have accelerated in the manner that it did."

Hilliard's contention, backed by his own experts who testified earlier in the trial, is that the accelerator system was defective. He maintains that two nylon pulleys became overheated and got stuck, leaving the throttle in an open position that caused the car to continue to accelerate, overriding the brakes.

Hilliard got James Walker, an engineer with Carr, to concede that if someone continued to pump the brakes, as Lee said he did, then the vacuum would be depleted in the brake system and that despite the force of the driver's foot on the pedal, the brakes may not work.

A point of contention is a brake light that both sides agree lit up at the time of the crash. The brake-light bulb on the left rear of the Camry broke during the accident, leaving the filament in a deformed position — evidence that the bulb had lit up.

Toyota's experts said the light went on because the crash caused inertia in the brake pedal, while Lee's attorneys said it lit up because Lee stepped on the brakes.

Hilliard got Stopschinski to acknowledge that while he had done a test to show that the light went on because of inertia, he had not conducted a test to show that the filament would be deformed.

"So for a company that spends this much money helping car companies get ready for trial and the amount of money you've spent in this case, why wouldn't you do this one test to prove that your theory is right?" Hilliard said.

Stopschinski countered that there is "plenty of literature out there that describes that."

Hilliard produced a study Friday that showed some variation to Stopschinski's testimony.

Randy Furst • 612-673-4224

Twitter: @randyfurst