A 2013 Volkswagen Passat with a diesel engine is evaluated at the California Air Resources Board emissions test lab in El Monte, California.

DETROIT — Auto industry insiders strongly suspect the emissions cheating scandal at Volkswagen is much wider and reaches higher up the corporate ladder than the company is letting on.

Volkswagen’s new CEO, Matthias Mueller, was quoted Wednesday as telling a German newspaper that the investigation so far has found that a few software developers tampered with the pollution controls on some of VW’s diesel engines. He said top executives would not have gotten involved in the software.

But industry experts and analysts say it’s hard to believe a few designers acted on their own to blatantly circumvent U.S. emissions tests.

“You know that simple software guys would never have the courage or the authority to initiate the cheating,” said retired General Motors vice chairman Bob Lutz. “They would want someone senior to sign off on it.”

VW has admitted that 11 million of its diesel cars worldwide have software that turns pollution controls on when the vehicles are being tested on a treadmill-like device and shuts them off when the automobiles are on the road. The trick enables the cars to get better fuel mileage while spewing illegal levels of smog-causing exhaust.

Mueller didn’t rule out a wider circle of offenders and said VW is “now clarifying the responsibilities in detail.” The automaker has suspended four people responsible for engine development and hired a law firm to investigate.

On Thursday, VW’s top U.S. executive, Michael Horn, is likely to face tough questioning on Capitol Hill about what he knew and when he knew it. VW said he will testify before Congress that he found out about the cheating software only a few weeks ago.

Experts say others in the company had to know about the cheating because the software controlled devices engineered by other departments. Those departments would surely have seen something amiss during testing of their own equipment.

Also, the cheating lasted for seven or eight years, and during that time, engineers and department heads would have changed jobs, widening the circle of knowledge, said Karl Brauer, senior analyst at Kelley Blue Book.

When some of the emissions violations were brought to VW’s attention by U.S. regulators in 2014, the automaker disputed the findings, fighting the Environmental Protection Agency for more than a year.

“Someone had to approve it initially and keep approving it for seven or eight years, and then start lying about it more when it was discovered,” Brauer said.

A VW spokesman in the U.S. wouldn’t comment on the analysts’ statements.


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