Seven witnesses implicated him. Why would seven witnesses do that? Has a conspiracy theory been investigated? What did they have to gain by lying? Why would they lie?

As for being under duress, well, forget the flowery language I could use... I think it's bullshit and, apparently, so do the people who executed him. Those witnesses gave their accounts. The man was convicted. THEN some of them recanted because they say they felt threatened during police investigations? Why did they not feel threatened when they wished to recant?

Which brings me back to an earlier question I asked... will these witnesses who lied under oath be tried for perjury?