Here’s two selected quotes from the article, although I can’t find anything from his wiki or anywhere else other than Trump that says he was a marxist, in fact he seems to be far more neoliberal than anything else:

That predilection would shape his professional outlook as “a pro-business economist, focused on what entrepreneurs see and how they think,” said Keith Collister, a Jamaica-based business journalist and economist who has worked with Dr. Harris over the years.

“The national industrial policy was anathema to Marxists,” said P.J. Patterson, Jamaica’s prime minister at the time. “What Don was propounding was the notion of a market-based economy where the private sector, not the government, was the engine of growth. There was nothing in there about state control of industry.”