Anoka, MN (Learfield News Service) -  A former Chisago County sheriff is charged with felony stalking, threats of violence and misconduct of an officer in Anoka County.

Prosecutors say ex-Sheriff Richard Duncan was actually the writer of a series of what he claimed were blackmail letters from someone named "Control Freak."

The blackmailer was reportedly trying to get Duncan and a female co-worker to attend a training session in Bemidji and stay overnight together in a hotel room. Duncan resigned from office shortly after admitting he was the one writing the blackmail letters in the fall of 2017.

The stalking charge carries a maximum ten-year prison sentence.