A Sac City man has been sentenced to five years in prison after failing to comply with sex offender registry requirements. According to Sac County District Court records, 44-year-old Michael Kruckenberg has been ordered to serve up to five years in prison after pleading guilty to the class D felony charge. Authorities say Kruckenberg was required to update his address with the Iowa Sex Offender Registry each time he moved. Law enforcement learned that Kruckenberg had failed to report a change of address from his Sac City residence. Additionally, Kruckenberg l often stayed at Lytton and Sioux City homes in violation of the Iowa Sex Offender Registry regulations. In 2011 Kruckenberg was convicted of second-degree sexual assault on a female victim 13 years of age or younger outside of Iowa. Kruckenberg was also convicted twice in Arkansas on failure to comply with reporting.