The Republican primary took yet another bitter turn as candidate Donald Trump tied the father of rival Ted Cruz to the 1963 assassination of president John F Kennedy.
In a telephone interview with broadcaster Fox News, Trump cited the tabloid National Enquirer newspaper, which published a photo of Lee Harvey Oswald distributing pro-Castro leaflets with a person the paper said was Rafael Cruz in New Orleans a few months before Kennedy's murder in Dallas.
"What was he doing with Lee Harvey Oswald shortly before the death, before the shooting? It's horrible," Trump said Tuesday.
Cruz reacted with fury, calling the front-running Trump a "pathological liar," and warning that the United States could fall into "the abyss" if Trump were elected president.
The verbal escalation came with voters going to the polls in the presidential primary in the Midwestern state of Indiana. If the billionaire Trump wins the state, his march to the conservative party's nomination could become increasingly inevitable.