A top executive with Volkswagen announced on Thursday that the software used to cheat emissions tests in VW vehicles was the work of rogue engineers. Years ago, an automotive parts suppliers brought the emissions issue to VW’s attention.

“This was a couple of software engineers who put this in for whatever reason,” Michael Horn, VW’s U.S. chief executive, told a House subcommittee hearing. “To my understanding, this was not a corporate decision. This was something individuals did.”

Horn added that three VW employees were suspected in connection with software that detects emissions tests, switches the vehicle engine to operate in a cleaner mode, and switches the engine back to a dirtier operation mode. Worldwide, the software was uploaded in 11 million cars. There are 500,000 vehicles in the U.S. with the software.

Despite VW’s rogue engineer claim, a report recently surfaced indicating that VW management received warnings from VW technicians about the emissions practice in 2011. The company never addressed the warning and never gave a reason why. In 2007, Bosch, an automotive parts supplier, also warned VW against using the emissions software.

For more on this story, visit the Los Angeles Times “VW exec blames ‘a couple of’ rogue engineers for emissions scandal” and Reuters “Volkswagen staff, supplier warned of emissions test cheating years ago – reports”