Jamison Stiles was fired from the force last year, after multiple women accused him of rape and sexual assault while on duty.
Washington County Deputy Prosecutor Brian Lamb said "evidence developed that made it impossible to move forward" with two of the six charges. He said he couldn't comment on the situation any further than that. Those two dropped charges stem from accusations Stiles fondled an intoxicated woman after arresting her, and taking her back to her apartment instead of the jail.
However, Lamb said he plans to move forward with the remaining rape, unlawful use of a police database, sex assault and residential burglary charges.
Stiles' rape trial is set for August 18. He is set to be tried for sexual assault on August 25.