Math Murder

During my last year of school, as I suffered desperately in my math class, I sat next to a fellow whose numerical struggles superseded mine only by a hair. On occasion he called upon me to assist him, but I suspected it was more about getting through the class unscathed than about learning anything: in our school, as long as one filled notebooks and gave the impression of making an effort, eviction from class was unlikely.
During the odd day here and there that he was actually present in the classroom, I detected an unsettling air of vacancy about my classmate that stretched beyond a lack of worry. He wore a perpetual expression of amusement and mockery, and his requests for help with this problem or that were so vague and nonchalant that it hardly mattered I was in the same boat as he, academically speaking. He accepted my answers to various questions and scribbled them in his dirty, broken notebook, shrugging off criticism when the teacher slashed red ink all over them: at least it looked as though he had tried.
For my part, it made me feel less hopeless to aid a fellow worse off than myself; and I considered it wise, too, not to refuse the strange, disquieting character that occupied the adjacent seat.
Two years later I saw a familiar name in a local newspaper: the fellow had been jailed for a grisly murder.
I do wonder at times how his life, and mine, and the life of the victim might have turned out had I taken a seat on the other side of the classroom.