The Square Root of Murder (Professor Sophie Knowles)

screen. “Not one student even close to a B,” he says. I look. Sure enough, no grade above a C and most below it. I know he wants me to commiserate about the pathetic abilities of Henley chemistry majors. I don’t comment. He turns the laptop back and pecks away at his keyboard. He shakes his head. “Dumb sophomores,” he says. “Dumb juniors. Dumb every student at this dumb college.”
    Now a picture started to take shape, and it wasn’t pretty. I saw Casey and her friends poisoning Keith—the details weren’t clear—and changing their grades on his laptop. I tried to chase away the picture. Of all the motives I could think of, this was one of the weakest. I imagined every college in cities and towns across the country losing a few teachers every year if this practice became popular.
    Something was missing in my theory. I played with the murderous picture in my head, running a blackboard eraser back and forth across it but it wouldn’t disappear.
    Out of the blue, Woody Conroy with his barrel of mops and brooms, invaded the scene that was taking over my vision. I heard Woody mention how he’d hung Keith’s Fellow award that morning. Pam entered the picture and I heard her tell me how she and her friends hadn’t seen Keith all day on Friday. Then Casey’s or Liz’s voice joined in, talking about the Fellow award on the wall.
    Someone was lying. Either Woody put that award up the day before, or the girls had been in Keith’s office the morning he was murdered. How else could they have seen the award on the wall?
    I left the scene, with the imaginary Woody and Pam and Liz and Casey arguing about who was telling the truth. My chips were on Woody.
    My mind reentered the interrogation corner of the Emily Dickinson Library.
    “Casey, did you change your grade?”
    Casey lifted her head from the cushion of her arms on the table. Her blond hair was wet from tears that had started when the subject of organic chemistry came up. Her face was streaked with poorly applied eye makeup. She opened her mouth but no words came out.
    Pam and Liz had reached us by now. Liz began stroking Casey’s back. Pam’s arms were folded across her flat chest.
    “We can explain,” Pam said.
    “I’m all ears.”
    “Let’s go somewhere else,” Liz said. “This whole place is creeping me out.” She wrapped her arms across her thin body as if she were freezing. Or at a crime scene.
    “I can’t stand this campus one more minute either,” Casey said, in a low scream, pointing toward Franklin Hall. She’d pulled herself together enough to stand up. “Can we go to, like, a coffee shop downtown?”
    “I have my car,” Pam said, before I could respond. She looked at me. “Unless you’re afraid to ride with us?”
    “Of course not,” I said.
    How foolish was this? Was I now the same obstacle to Casey’s college funding that Keith had been? I refused to believe these young women would harm me.
    Still, I hoped Bruce wouldn’t travel too far out of range of my cell.
     
     
    We sat at a round table in Back to the Grind, only a few blocks from campus, an easy walk in better weather. The place wasn’t air-conditioned, but a large fan kept the room bearable. The ride over had been silent except for the sounds of an old AC/DC album in Pam’s CD player.
    Now with various levels of caffeine drinks in front of us, it was still silent. Until Casey started to tear up again.
    Pam put her hand on Casey’s arm and the waterworks stopped. “We just wanted to help Casey out,” Pam said.
    “So you two were happy with your Cs and Ds?” I asked, addressing Pam and Liz.
    “We just thought, while we were there, you know, we might as well up ours a notch, too,” Liz said.
    I rolled my eyes, shook my head, and otherwise showed my extreme disapproval.
    “Oh, come on. How many students does Dr. Appleton really flunk in the long run?” Pam asked in an updated version of “pshaw.” “Not that many when it comes to final grades. He likes to scare us is all. I’d have come out fine one way or the other.”
    “I knew I could make it up,” Liz said. “Honestly, a C or D here or there isn’t going to ruin my life. But Casey would have had to leave school.”
    “And that was worth your teacher’s life?”
    The girls turned to me, eyes all wide, mouths open.
    I heard the beginnings of sentences.
    “Oh, no . . .”
    “We didn’t really . . .”
    “How could you think . . .”?
    Their protests were intermingled; I couldn’t