It is rare that a prosecutor's office will investigate a possible crime. They tend to conduct follow-up only after a case is referred to them for prosecution from a local law enforcement agency.
The local prosecutor is not likely to listen to you or your "evidence" and suspicions of how the local police got it wrong. Your only real recourse is to try and work with the local police to resolve the matter, or, to pursue a civil action (lawsuit) against the perpetrator of whatever offense you think you can prove. Provided, of course,that a court recognizes that you have standing to proceed with a suit.
You might want to consider consulting an attorney to see what they might suggest as to how to proceed. He may tell you that you are barking at the wind ...or, he may say you have a case. We can't see. I CAN say, however, that many people in your position see crimes and evidence when there is none - at least none that can gain any traction in a courtroom. This is why it might be a good idea to have an attorney go over what you know and what you think you know. That attorney might be able to put a different perspective onto the matter for you.