Earlier quoted context omitted.
That's the problem, though. There was an in-depth investigation planned, thanks in part to that doctor. It was then cancelled by the officials in charge, with the excuse that the doctor's work was improperly conducted. That action with that excuse was arguably more harmful than anything else in this entire story.
If not that excuse, they would have come up with another excuse to not investigate. What we are missing is the reasons behind the coverup.
I understand the urge to call it a coverup (I am very suspicious of this as well), but it is entirely possible that this is also just good old fashioned incompetence.
Professionals in some fields, especially medical, often do not like to be doubted and write off other people's disagreement with them as clearly wrong. I can easily see this being the case here.