A principal accused of setting fire to the North Dakota high school where he worked had passed background checks and came recommended by clergy and mentors in other states. Thomas Sander is charged with felony arson and endangering by fire or explosion after a fire that heavily damaged Trinity High School and forced its closure. He remained jailed in lieu of a $500,000 cash bond. “He’s a graduate of a well-known and prestigious prep school in St. Louis. He has graduate degrees in administration,” said Monsignor Patrick Schumacher, the board chairman for Dickinson Catholic Schools. “With his qualifications, recommendations and work ethic, we made the decision to hire him.” The Dickinson job was Sander’s first full-time principal position, according to Schumacher. He said Sander had a good work ethic but did make some mistakes. “I will not say there were no issues. But I will say there’s no way in my mind the issues could have added up to this.” He declined to say if Sander was sanctioned for any reason during his tenure. “There’s a lot of speculation as to how this may have happened,” he said. “There are no answers.” Classes were called off for the week.