What is the statute of limitations in Iowa for sex offender failure to register? (aggrivated misdemeanor)

I had an indecent exposure 1st offense to 17 yo and so must register.

Police claim I set up residence in IA for more than 5 days and so I should've registered. I have evidence (bank, restraunt reciepts) to show I was 300 miles away.

cops got an idiot judge to sign off on a warrant