Find the highest qualified lawyer in this particular field, and,
Learn if that lawyer would charge for an initial consulation.
In any case, dealing directly with law enforcement officers is a roll-of-the-dice. One must remember that their job is to enforce the law, not to provide legal advice or assistance.
In the same way that one does not expect to hire a qualified person in any field for free, so too does the situation exists with lawyers. Furthermore, if a lawyer (other than a public defender, etc.) does agree to work for no fee, oftentimes the service provided is less than perfect: the work that pays will be done first.
Aside: in my experience (!), law enforcement officers appear to better-trained than years ago.
