Politico's James Hohmann writes:

A forthcoming book raises serious doubts about a key piece of evidence that led a House committee to conclude in 1979 that President John F. Kennedy was likely killed as part of a conspiracy.

University of Virginia political scientist Larry Sabato commissioned a scientific analysis of the Dallas Police Department’s Dictabelt recording of scanner traffic from Nov. 22, 1963, as part of his research for “The Kennedy Half Century: The Presidency, Assassination, and Lasting Legacy of John F. Kennedy.”

Investigators for the House Select Committee on Assassinations relied heavily on the tape to say there was a high probability that Lee Harvey Oswald was not the lone gunman.

Sabato doesn't dismiss every conspiracy theory about the JFK assassination, and he concludes that we'll probably never know the truth of everything that happened. People like to wave coincidences around, but the truth is that most of them are conspiracy theorists because they just don't want to believe that one man can toss the country into chaos. Not all conspiracy theories are bullshit, but bullshit clings to conspiracy theories the way iron filings are attracted to a magnet.