German law enforcement raided a former NATO bunker suspected of being the location of a hosting service used for illegal activities.

On Friday, investigators said a data center had been installed in the former military bunker that specialized in bulletproof hosting services, as reported by the Associated Press.

Bulletproof hosting services generally run under a “don’t ask, don’t tell” philosophy. Servers are generally found in countries where there are lax or non-existent laws on website content and intellectual property infringement, and hosting providers do not interfere with what content or services their clients provide when leveraging their bandwidth.