Censorship and covering information up is not a new idea that came up in the last 200 years . It has around for centuries in many forms from burning books to burning entire cities . It is form or erasing either a religion , culture , mindset or it is to send a message to others by dramatic examples as in JFK’s assignation . In the case of the Scientist that were brutally murdered or full blown vanished it was both. Look at the peculiarity in the time frame . The fact many of them knew each other . What were they working on that may have gotten them killed ? What were they about to expose ?