What is the fine-grained topic of the following text: Considering knowledge of what happened in those cities were kept secret for like 50 years by the US (they were worried it'd turn public opinion of the world against them) it wouldn't surprise me if witnesses or those that heard 2nd hand used it as inspiration or as a way to leak the stories without breaching some sort of NDA. Only return the topic.
Potential influence of US government's cover-up of past events on public stories or rumors