Berlin prosecutors are investigating ex-German state minister Eckart von Klaeden over a potential conflict of interest after Chancellor Angela Merkel’s former ally joined carmaker Daimler as a lobbyist, a spokeswoman for the prosecutors confirmed on Sunday after a media report.

Klaeden, a former treasurer of Merkel’s Christian Democrats who spent the last four years in a senior role, said in May that he would quit the government after Germany’s Sept. 22 national elections to take up the position of chief political lobbyist at Daimler.

Germany weekly magazine Der Spiegel reported on Sunday, without citing any source, that Klaeden, who was known to have met with Daimler representatives while still in politics, had access to three confidential government papers between January and May 2013 on the EU’s planned regulation of auto emissions.

Germany last month blocked an agreement among EU member states to cap car emissions, arguing the plan would cost jobs and hurt premium carmakers such as Daimler’s Mercedes-Benz brand as well as BMW and Audi.

A spokeswoman for the Berlin prosecutors told Reuters on Sunday that an anonymous complaint has been filed against Klaeden with prosecutors, who are investigating on the grounds of a potential acceptance of benefits.

Klaeden, who joined Daimler on Nov. 1, rejects the charges and pledged to fully cooperate with legal authorities, German business daily Handelsblatt said in an advance release of an article published on Monday.

“It’s a completely normal procedure that prosecutors start investigations because an anonymous complaint was filed,” a spokesman at Stuttgart-based Daimler said. “We have no doubts at all about the integrity of Mr. Klaeden.”