I was the victim of a voyeurism (felony sex offense) in AZ. The man confessed in his first language of spanish to a bilingual officer (not a certified interpreter) and the police department lost the recording. The state prosecutor now wants to prosecute him with a misdemeanor due to the lost recording and the lowered credibility of the officer -- which I am not ok with. Do I have any recourse against the police department for this?
No. You have no legal grounds for a suit against the agency.
You can raise heck in the media if you wish. You can also sue the dickens out of the suspect. But the agency acts on behalf of the people, not you, so you have no cause of action against them for losing the evidence.
Besides, even with the confession, the case might have been weak. It could be that they have a strong misdemeanor case but a weak felony one so they made the decision to pursue the case they stand the best chance of winning. It happens like that all the time.