It's getting more and more difficult to believe that Volkswagen employees were unaware of the company's diesel emissions-cheating software.

A top Volkswagen technology executive reportedly created a PowerPoint presentation in 2006 detailing how to cheat diesel emissions testing in the U.S., reports the New York Times.

According to two anonymous sources who claim to have seen the presentation, the company knew its diesel cars polluted far more than advertised — as much as 40 times the legal limit in the U.S. — and declined plans to install improved emissions systems.

Engineers realized early on that if they adjusted emissions systems to meet the much more stringent U.S. emissions laws, the systems would degrade prematurely. Instead, the company implemented a cheaper solution, the so-called "defeat device" software created by Audi in 1999, according to Reuters.

It is not clear now many VW employees saw the presentation. Earlier reports indicated as few as 20 people inside VW knew of the plot. However, that number is increasingly becoming less and less credible.

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