> How do you know it?

The burden of proof rests on the person alleging it happened, not the person saying there is no evidence. You're asking me to concede that something must have happened in secret unless I can prove a negative. To top it off, Der Spiegel very strongly suggests that they just recently learned of the matter in the editor's note on the left hand of the page. Nowhere in their reporting (or, to my knowledge, anyone else's reporting) are they claiming that the government forced them to withhold a story.

> FOIA records on FBI and CIA show again and again ...

Could you provide links to these FOIA documents?