And if the alleged payer is outside the field, this might also be relevant to the public interest in other regards. (For example, if they're trying to suppress this, what else are they trying to do. Even if it turns out the research is invalid.)
I agree. Asking questions which are normal in my own field resulted in stonewalling and obvious distress. The worst thing being this leading to the end of what was a good relationship.
If not, you might consider whether you have actionable information yourself, any professional obligations you have (e.g., if you work in science/health/safety yourself), any societal obligations, whether reporting the allegation would be betraying a trust, and what the calculus is there.