The presidential car quickly traveled to nearby Parkland Hospital, where the president was pronounced dead.
Hill recounted the aftermath of Kennedy's assassination and his service under President Lyndon Johnson. He continued to work for the Secret Service until his retirement.
McCubbin had one final question for the old agent.
"It's been almost 50 years. Many people say there was a conspiracy. What is the truth?"
Hill said there was no evidence of a conspiracy to kill Kennedy.
"Only three shots were fired in Dealey Plaza," Hill said. "All three shots came from the same direction and were fired by the same rifle, by the same individual.
"All credible evidence shows that Lee Harvey Oswald acted alone."