Jim Garrison: They killed Robert F. Kennedy. He won, and they killed him. They shot him down.
Liz Garrison: Oh God. Both of them? They got both brothers?
Dean Andrews: Kennedy's as dead as that crab meat, the government's alive and breathing. You gonna line up with a dead man, Jimbo?
Jack Ruby: Oswald.
Answer: Lee Harvey Oswald was very sympathetic to the communist ideal, and lived in Russia for a while. He probably adopted the accent as an affectation towards that end.
Grumpy Scot