(Robbinsdale, MN)  —  A Robbinsdale teacher is facing allegations that he sexually assaulted two boys in the past.  Matthew Bertsch was arrested Tuesday at the FAIR School in Crystal and is being held on 300-thousand dollars bail.  He is charged with two counts of second-degree criminal sexual conduct and a child pornography count.  Authorities say he abused two boys he was related to “well over 100 times” and for several years.  Bertsch is due in court today.