The Square Root of Murder (Professor Sophie Knowles)

one more chance with the Triad. Casey was the Queen of Bling, with a different set of shiny, tinkling baubles every day. While I couldn’t even stand to wear a watch on hot days, Casey decorated her wrists, ears, neck, toes, fingers and patches of bare skin with jewels and decals no matter what the weather.
    It was tough to search out her small face with today’s distraction, a matching beaded set of earrings, necklace, and bracelet, in shades of red and purple. I was tempted to ask if she’d made them herself, and if so, had she bought the beads at Ariana’s shop, but that would have compounded the distraction.
    I decided to try a new tactic with the third interview of the day, not counting the dean’s with me, and start with the elephant in the room.
    “Casey, I felt you had more to say yesterday, when we were chatting outside Franklin Hall. Is there something you want to tell me?”
    “We were at the party for Dr. Bartholomew, like everybody else, then we went to the dorm,” she said.
    Not again. I sent a soft, compassionate breath her way. “Casey, I know Pam can be a little intimidating—”
    “I don’t have anything more to say, Dr. Knowles. Can we just get to my grade for the class? Please?”
    Casey’s “please” was a drawn out plea. That and her eyes, on the verge of tears, got to me. Time to move on. I knew these girls were hiding something, but when push came to shove, I couldn’t beat up on this child.
    Casey was not doing well in applied statistics. To keep her scholarship she needed at least a B in each class. In my class she was hovering around C, plus one day, minus the next. I told her the kind of research paper she’d have to do to bring her grade up, and that she’d need to take an exam.
    In my experience, there were two kinds of test takers, those who preferred oral exams and those who dreaded them. I gave Casey her choice.
    “Oh, my God, I love orals,” Casey said. “I get all clutched up when I have to write and I can’t explain myself because the questions are too . . . too . . .”
    “Too specific?”
    She nodded. “Like Dr. Appleton’s. Like, with true/false it’s do or die”—she clamped her hand over her mouth—“I didn’t mean it that way.”
    I patted her other hand, the one with six inches of thin multicolor spangles. “I know you didn’t mean it. You had that extended organic chem class with Dr. Appleton this summer, right?”
    “I like that. ‘Extended.’ Actually it was makeup, since we did so badly this spring.”
    “Do you know yet how that will be wrapped up?”
    “Uh-huh, that new teacher, Ms. Bronson, is taking over now as far as working out our grades.”
    “I’m glad it’s taken care of. What grade do you have going in?”
    A simple query, to show my interest, not meant to be a trick question. I was past trying to dupe the girls into giving me information I could use to clear Rachel. And I’d decided some time ago that getting to the truth of who killed Keith Appleton was more important even than a single student. I needed to follow the evidence and the logic of the murder, no matter where it led.
    I was taken aback to watch Casey stumbling over my simple question and looking as rattled as if she had one million dollars riding on her answer. She ran both hands through her unruly curls. “Uh . . . an A,” she mumbled.
    That was a surprise. But why mumble an A when it might be the first one you’ve had in a long time? Maybe I’d heard wrong.
    “Did you say an A?”
    “I have an A going in,” she said, not much more clearly.
    “Good for you. I thought you were struggling with that class.”
    “I, uh, was, but I, uh, pulled it up.”
    I looked across the table at Casey. She hadn’t been this flustered even yesterday while she was lying to me. She fidgeted in her chair, looked up to the ceiling and down to the table, glanced back over her shoulder toward the lobby, and then repeated the sequence. My guess was that she wished she could beam Pam and Liz over here to bail her out. Pam and Liz, on their part, were inching closer to us as it became increasingly obvious, even from a distance, that Casey was in distress.
    Casey’s behavior threw me back to being in Keith’s office a few days before his death.
    Keith is working on his laptop, updating his organic chemistry grade sheet. He’s in a hurry to finish up and print out the sheet to take to his class. “Look at this.” He spins his computer in my direction and shows me the