Michael Horn, the CEO of scandal-hit automaker Volkswagen's U.S. operations has admitted that he was told the company was cheating on emissions standards in early 2014. The revelation was made in a testimony that he will present to a congressional committee investigating the scandal Thursday.

In a prepared statement to the committee, Horn, president and CEO of Volkswagen U.S., said he was told in the spring of 2014 that there was a “possible emissions non-compliance” situation that could be remedied. 

He added that he was informed that government agencies could conduct “engineering tests which could include 'defeat device' testing or analysis. I was also informed that the company engineers would work with the agencies to resolve the issue.”

Up to 11 million of the company's four-cylinder diesel cars worldwide were fitted with a software-based “defeat device,” which detected when a vehicle was being tested by authorities for emissions levels. During testing, the software would reduce the vehicles' emissions levels to allow them to pass testing. On the road, however, the vehicles would emit up to 40 times the level of pollutants permitted under regulations.

However, after the written version of the statement was made public, Volkswagen spokeswoman Jeannine Ginivan told media outlets that Horn would testify he only found out about the cheating software "over the past several weeks."

Horn's statement says that Volkswagen did not inform U.S. authorities about the scandal until Sept. 3, 2015.

In his testimony, Horn joined other senior Volkswagen managers in apologizing for the scandal, saying that the company had broken the trust of its customers. He added that Volkswagen was conducting a worldwide investigation into the scandal, which would identify responsible parties and hold them accountable.

Who exactly is responsible is a matter of some debate in the industry. On Wednesday, Volkswagen's new CEO, Matthias Mueller said: “According to current information, a few developers interfered in the engine management,” adding that he did not think the board or management made a decision to use the “defeat device” software.

Industry experts, however, expressed skepticism that relatively junior employees would take the decision on their own to have the company's vehicles skirt emissions regulations.

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