It's not really. Police lie constantly, especially when it would implicate them. Their statements carry zero information except where they provide positive publicly verifiable evidence. Unsettling and sad, but its the truth.
Given the circumstances, I would say you're never going to know the truth about these deaths with the possible exception of documents declassified or admissions of guilt decades after the fact. The question is if you are a political activist, is do you take these deaths seriously even if you can't prove they are foul play? Given the record of the government, I just can't rule it out.
