Secretary of State John Kerry has said former president John F. Kennedy's assassin may not have worked alone.
Kerry has become one of the highest-ranking politicians to publicly doubt that Lee Harvey Oswald was the lone conspirator in Kennedy's murder.
Kerry admitted to a journalist that he was suspicious of the government's official finding.
According to news.com.au, Kerry in an interview broadcast on NBC, timed with the 50th anniversary of Kennedy's death, said that to this day he has serious doubts that Oswald has acted alone.
He said that he has doubts that Oswald was motivated by himself, but he has serious questions about whether the investigators got to the bottom of Lee Harvey Oswald's time and influence from Cuba and Russia.
Oswald, who was charged with Kennedy's November 22, 1963, assassination, is known to have lived in the Soviet Union ahead of the attack, moving back to the US in 1962.
He also attempted to visit Cuba, via Mexico, in the months before Kennedy's assassination.
The US government's official investigation into the shooting ignored the possible influence of communist nations, leaving theorists, Kerry among them, to speculate.
Kerry added that he met Kennedy while he was working with his brother, Teddy, during the younger sibling's 1962 senatorial campaign, the report said.
The three men went sailing together in Washington.
