Unmarked police car responding - Audi A6 Armed Response with siren + lights - YouTube
How To Spot One Of The Latest Unmarked Police Cars - SuperUnleaded.com
Swiss unmarked Audi S4 radar cars Photo Gallery
Unmarked car hi-res stock photography and images - Alamy
Croatian unmarked police. Plus, I can confirm, from my own personal experience, they also drive a black Audi A4. Me being in the same car didn't help my case. : r/Audi