https://en.wikipedia.org/wiki/The_Anderson_Tapes
>In the course of searching the building, the police discover some audio listening equipment left behind by the private detective who was hired to check up on Ingrid and track it to find Anderson in critical condition after having tried to escape. To avoid embarrassment over the failure to discover the robbery despite having Anderson on tape in several surveillance operations, and since many of the recordings were illegal, each of the agencies orders its tapes to be erased.