Joshua Brandon Pillault is scheduled for trial on Feb. 25 in U. S. District Court in Oxford. He has pleaded not guilty.
Pillault is accused of making the threats while playing the online game "Runescape." His lawyer wants more time to prepare.
Court documents say he made references to an attack on Oxford High School, where he is a former student.
The indictment says he mentioned acquiring guns, ammunition magazines, Molotov cocktails, and pipe bombs and using them to level the school.
Pillault underwent a psychiatric evaluation and the report was submitted to the court, but it was sealed.