A German broadcaster reported that Volkswagen chief executive Herbert Diess was given a memorandum warning that the company could face legal action in the U.S. due to its diesel cheating shortly before the scandal broke.

A former Volkswagen employee revealed to the public prosecutor that he gave a document to Diess on September 14, 2015, detailing how Volkswagen had lost its credibility with U.S. authorities and was going to be charged. U.S. regulators ultimately disclosed VW’s violations on September 18, 2015.

Diess was the automaker’s brand chief at the time and took over as company chief executive from Matthias Muller in April, 2018.

VW didn’t anticipate the magnitude of the dieselgate scandal

Automotive News reports that Volkswagen’s senior management is being investigated by prosecutors in Germany to determine whether or not the car manufacturer violated disclosure rules.

In a statement, a Volkswagen spokesman said that Diess, Volkswagen supervisory board chairman Hans Dieter Poetsch and former Volkswagen chief executive Martin Winterkorn won’t comment on the ongoing investigation.

Der Spiegel reports that Diess was present at a meeting on July 27, 2015 when senior engineers and executives discussed the best way to deal with U.S. regulators.

VW’s former chief financial officer, Dieter Poetsch, believed that regulatory penalties tied to the emissions issue would only total about 150 million euros ($172 million). Consequently, the firm thought that it didn’t need to disclose to shareholders the potential fallout and could cover the costs with already accrued legal provisions.

Volkswagen now says the scandal has cost it more than $27 billion in penalties and fines around the world.