He is a graduate of the Fond du Lac Tribal and Community College in Cloquet. 8:23 am, Apr. 10, 2021 × Osakis Police Officer Preston Oetterer was hired last July, but in March became the police department's newest full-time officer. He replaced Mark Grinstead, who now works for the Sauk Centre Police Department. (Celeste Edenloff / Echo Press) Growing up in the small town of Finlayson in eastern Minnesota, Preston Oetterer feels right at home in Osakis. The new full-time police officer says he needed roots and that Osakis, even with its population that is more than five times that of Finlayson, is the perfect fit.