In the case of the microbiologists, it may not always have been them blowing the whistle, but the chinese have been infiltrating for a long time. They would be just as like to shoot a principal investigator just so they could get his or her lab space.
A possibility. I’m not certain, but iirc the rash of tv news reports began in the 80’s. I don’t know if lab spots & Chinese students were a problem back then. Could have been.