"Today, I reflect on the events of the last two weeks in utter dismay that under the veil of anonymity an individual was given the power to disrupt the plans for leadership at Washburn High School and leave me with an uncertain future," Exner wrote.
Exner said that when he decided to leave Ubah Medical Academy, where he was the associate director, he was "in good standing" with the school, and held a contract to return for the 2013-14 school year. He denied tampering with students' test scores.
"While at Ubah, I continued to address concerns as they were raised within our school or the larger purview of the MDE openly and honestly," the letter reads. "The allegation that I changed students' answers on state assessment tests is absolutely false"
Exner also said he initially applied for a different position with the Minneapolis Public Schools, but was asked to instead apply for the Washburn principal position.
"I am saddened that I will not be the leader who restores harmony and excellence within Washburn's halls and the greater community," the letter read.