How do you know it? What sort of interference would you expect these days anyway? The secret order signed by Angela Merkel herself ordering to stop the story or face lifetime in prison?
FOIA records on FBI and CIA show again and again that western governments are not ashamed to use misinformation, defamation, subversion and provocations. In fact, they have become extremely skillful at these hard-to-prove-yet-so-effective-against-civilian tactics.
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?