Given that this is part 3 of a series about a drug-lord, I suspect that the author is hinting/leading us to think that the "unknown financier" is Paul Le Roux,

Given that this is part 3 of a series about a drug-lord, I suspect that the author is hinting/leading us to think that the "unknown financier" is Paul Le Roux, without blatantly stating it. (either as a teaser for part 4, or because there's not enough dots connected yet).