Sadly, this will likely have to go to court where he (sailor) will have to sue the county / state to get it expunged. If it does go that far, I agree with him receiving compensation for his troubles.
RPM, if what you say is true, that there is collaboration amongst the DA and the narc officer, then they deserve to be punished for lying under oath...
The other side I wonder about is identity theft... maybe they really are looking for someone who passed themselves of as the sailor.