despite claims otherwise to some of their less ML compatriots, this seems to have been the plan more or less from the start. Several of the revolution’s leaders were executed for not being ML-leaning.
Confirmed by William Alexander Morgan, who became disillusioned with Castro, and was then executed despite how much he'd helped the revolution.
He was charged with planning to lead them, though I'm not sure if that was actually true or just a charge to slap on him before the execution. He did smuggle arms for the counter-revolutionaries, but only after his comrades and friends were being arrested for counter-revolutionary activities.