  Beyond these problems of scope lies an epistemological difficulty: Lustration purges and exclusions frequently, though not always, rely on testimonials and security service files which are often of dubious accuracy. The files are often rife with human error, exaggerations, and omissions. The most valuable Communist informants and collaborators were often missing from surviving secret police files (many were destroyed or “disappeared”, probably into KGB possession) or were shielded during the process (Minow  2000).[37]  On the other hand, employees of the security services often embellished their accounts and added false informants in the period before an audit so that they could meet or exceed their prescribed  quota.[38] 