Spirit Lake, IA (Northwestiowa.com) — The Dickinson County Attorney’s office has dropped charges of operating a motor vehicle under the influence of alcohol against a former law enforcement official.

A DNR officer charged Mike Martens – who was then the Emmet County Sheriff – last summer, saying he observed the Sheriff operating an ATV on a prohibited recreation trail on the west side of Big Spirit Lake.

Assistant County Attorney Kevin Maughan writes in court documents that there was insufficient evidence to convict Martens and results of a sobriety test were within the margin of error.

Martens retired as Sheriff December 31st.