A second investigation? Have you ever heard of the House Select Committee on Assassinations?
You're the one suggesting that a non-government investigation would be preferable. Why not explain why and then explain how such an investigation would work? What possible materials could be gathered by a private entity that would have greater evidentiary value than materials gathered by law enforcement agencies?
You mean the HSCA investigation who said
"The HSCA found that although the Commission and the different agencies and departments examining Kennedy's assassination performed in good faith and were thorough in their investigation of Lee Harvey Oswald, they performed with "varying degrees of competency" and the search f
or possible conspiracy was inadequate.:2 The HSCA determined, based on available evidence, that the
probable conspiracy did not involve the governments of the Soviet Union or Cuba.
The committee also stated that the conspiracy did not involve any organized crime group, anti-Castro group, nor the FBI, CIA, or Secret Service."
Seems your HSCA don't support your view that there was no conspiracy.