Oswald's very presence in the TSBD is prima facie proof of a conspiracy. In law a prima facie case is one based on facts legally sufficient to establish the case unless the facts presented are disproved. The FBI had been involved with Oswald as far back as Oswald's "defection" to the USSR and so the FBI knew of Oswald's so-calledprocommunist background. The FBI knew of Oswald's presence in Dallas and, in particular, of his employment in the TSBD and yet the FBI did nothing to keep closer tabs on Oswald or even remove him from the TSBD during JFK's visit. The FBI did nothing to prevent an individual like Oswald who, by any standards, should have been considered, rightly or wrongly, to be a potential security risk ( If Oswald was considered by some to be in the category of a "nut" after the assassination, then what category was he in before the assassination? ). Since when are potential "nuts" allowed to get so close to a President of the United States? Therefore Oswald's presence in the TSBD must be seen for what it really is - prima facie proof of a conspiracy - whether or not Oswald actually knew or did not know of a conspiracy to assassinate JFK.
The questions that must be asked are:-
A/ Why did the FBI do NOTHING?
B/ Did someone instruct the FBI to leave Oswald "in place"?
C/ Who had the authority to call off the FBI?
And the underlying reasons why the FBI did nothing and left Oswald "in place"?
The firsttwo rules of a conspiracy -
1/ Make sure nobody compromises the conspiracy.
and
2/ Make sure nobody [b]but nobody[/b] screws up the patsy.