Volkswagen suspended its head of external relations and sustainability amid accusations that the carmaker funded tests that exposed both monkeys and humans to diesel fumes.
According to several reports, Volkswagen announced Tuesday that Thomas Steg voluntarily stepped away from his position. He will be suspended until an investigation into the matter is complete.
Steg admitted to knowing about the tests in question and failing to inform the company's CEO at the time.
The New York Times first reported on the tests last week, which were conducted by researchers commissioned by Volkswagen and other automakers back in 2014.
The report comes more than two years after Volkswagen admitted to cheating U.S. diesel emissions tests.
Reuters quotes the company's CEO as saying Monday, "Over the weekend we had to learn once more that there is still a long way ahead of us to regain lost trust."