Former middle school assistant principal Brandon Mark Bjerknes of Bemidji admitted Thursday in U.S. District Court that he is guilty of producing child pornography, plus coercing and enticing children.

ST. PAUL, Minn. - A former assistant principal at Bemidji Middle School has pleaded guilty to producing child pornography.

Thirty-five-year-old Brandon Mark Bjerknes of Bemidji also admitted Thursday in U.S. District Court to a second count of coercion and enticement of a minor.

Prosecutors say that while assistant principal, Bjerknes posed as a teenage boy and used social media to contact girls and boys in middle and high school and direct them to send him explicit photos. He also engaged in sexually explicit conversations.

Authorities say Bjerknes contacted more than 50 victims; some were students Bemidji Middle School.

Bjerknes was assistant principal there for three years before resigning in April.