The man who silenced the apparently CIA-linked Lee Oswald on November 24, 1963--the apparently CIA-linked Jack Ruby--died of cancer on January 3, 1967. As Crossfire: The Plot That Killed Kennedy by Jim Marrs recalled:
"On December 9, 1966, two days after his new trial site had been announced, Ruby was moved from the Dallas County Jail to Parkland Hospital after complaining of persistent coughing and nausea.
"Docotrs initially diagnosed his problem as `pneumonia.' The next day, however, the diagnosis was changed to cancer...
"Bruce McCarty operated an electron microscope at Southwest Medical School near Parkland...He was called back to work during the holidays in 1966 to make a study of Ruby's cancer cells...
"McCarty confirmed that Ruby's cells were microvilli, indicating his cancer originated in the digestive system. He was shocked when it was announced that Ruby died from lung cancer.
"Could Ruby have been injected with live cancer cells, which could account for the presence of the microvilli?...
"While none of this information established beyond doubt that Jack Ruby was somehow eliminated through cancer, it certainly shows there is cause enough for researchers to be highly suspicious of his sudden and convenient death..."
The same book also observed:
"At least one former Dallas lawman offered a more mundane explanation for Ruby's sudden and rampant cancer. He told another: `...They just took Ruby in for X-rays...While he sat there for 15 or 20 minutes or more, they just left the X-ray machine on him.'"