2. HSCA reported, based largely on acoustic evidence, assassination likely was a conspiracy.
One of the Dallas PD motorcycle officers in the motorcade apparently recorded the sounds during the assassination, due to a faulty radio microphone that stayed on, leaving impressions on the Dallas HQ Dictabelt recording system. The HSCA did a heck of a job recreating the acoustic signatures, shooting rounds from various locations around Dealey Plaza and comparing the sound wave forms to what the Dictabelt revealed. Details.
From Mary Ferrell:
House Select Committee on Assassinations (HSCA)
The House Select Committee on Assassinations was the second major investigation of the JFK assassination, following the Warren Commission by nearly a decade and a half. The revelations of the Church Committee were profound in the 1970s, and efforts to re-investigate the assassinations of the 1960s picked up steam. The airing of the Zapruder film on television in 1975, showing Kennedy reacting “the wrong way” to a bullet from the rear, was a defining event which helped push the momentum over the top.
Congress authorized an investigation into the murders of John F. Kennedy and Dr. Martin Luther King, Jr. Chief Counsel Richard Sprague ran into early troubles, butting heads with the CIA over secrecy oaths among other matters. He was eventually forced to resign, and the investigation was taken over by G. Robert Blakey.
After a few years of work, the House Committee issued a Final Assassinations Report, along with 12 appendix volumes on each of the murders. In the JFK case, the HSCA found that "Kennedy was probably killed as a result of a conspiracy," based in large part on acoustics evidence which captured the sound impulses of gunfire from more than one location in Dealey Plaza. In the MLK case, the HSCA’s verdict endorsed a lone-gunman conclusion but "there is a likelihood that James Earl Ray assassinated Dr. Martin Luther King as a result of a conspiracy."
With the declassification of the HSCA’s files in the 1990s, researchers know much more about that body’s internal workings. In the areas of the medical evidence and Oswald’s trip to Mexico City, two areas the Committee focused heavily on, it is clear that the HSCA did not tell all that it discovered.
Based on new evidence indicating CIA withholding of key information, HSCA Chief Counsel Robert Blakey in 2003 wrote a scathing letter about CIA obstruction of the HSCA inquiry: "I now no longer believe anything the Agency told the committee any further than I can obtain substantial corroboration for it from outside the Agency for its veracity." more
The HSCA asked the Department of Justice to continue the investigation. After Jimmy Carter's defeat, Ronald Reagan and the Justice Department refused.
The CIA, especially, stonewalled the HSCA investigation, sending in George Joannides as their liaison. Of course, the CIA didn't mention the fact Joannides had been CIA management in New Orleans when Oswald was there in the summer of 1963.