As a Libertarian concerned about the damage that can be done by overweening officials at all levels, I am eager for the Feds to keep states on the right side of the constitution. It is an ethics violation for a prosecutor to prosecute when he lacks clear and convincing evidence and even more so when it is clear that there is exculpatory evidence. Every day of delay is another day of $500 / hr legal expenses that can ruin a defendant. Given the expenses of a defense it is a violation of due process to expect someone to pay for his defense when he is clearly innocent.
There is no state right to prosecute the innocent.
That is a matter for civil resolution and it seems to me these players will have a very strong case against the Durham authorities. As a Libertarian, you should be more cautious of invoking the Federal hammer.