Much of it, but not all, has been uncovered by the work of independent researchers over 47 years.
They are willing to accept it was not the work of one man, but do not want to pursue the matter further.
It may be unrealistic, however, to expect to find hard evidence to answer the question, who else was involved & why?
I believe, however, it is helpful to admit, it was clearly not the work of one man. At least that's a start.