Former Audi CEO Rupert Stadler was released from a German prison this week after spending four months behind bars.

While never charged, Stadler was taken into custody over concerns he would suppress evidence related to a German investigation into the Volkswagen Group diesel emissions cheating scandal that has been in play since late 2015.

German prosecutors on October 16 settled with Audi by serving the automaker with a $927 million fine for its involvement in the scandal. Audi's VW Group parent was served with a $1.16 billion fine.

Stadler's release comes after a successful appeal of a court ruling in August that kept him in a prison since his June arrest. However, prosecutors warned that there was still evidence against several individuals, including Stadler, in an ongoing criminal probe into the scandal.

Stadler is now out of a job as he lost his roles as CEO at Audi and a director of the board at the VW Group on Oct. 2.

The fallout from dieselgate has so far cost the VW Group and its brands $31 billion in buybacks, fixes, and fines in Europe and North America. While a number a number of individuals have been charged, so far only two have received prison terms, in both cases in the United States. They include Oliver Schmidt who in 2017 received a seven-year prison sentence, and James Liang who that same year received a four-year sentence.