The Square Root of Murder (Professor Sophie Knowles)

I turned to face Archie McConnell.
    He, on the other hand, was smiling. It was the smile of victory.
    “I like numbers,” I said.
    “You would.”
    He ushered me into a large office with room for three desks and several extra chairs. A lot of coming and going and paper shuffling throughout the area, but no one was seated.
    Archie took his place behind a desk with his name on it and indicated the chair I should take. We both knew that I was about to concede defeat. My role as unofficial police consultant had come to an end.
     
     
    Archie was nicer to me than last time, leading me to believe I was no longer a viable suspect in his mind. He nodded politely as I announced that I had information from some of my students and from the janitor at the college. I hated to drag Woody into the morass of those who lied to the police, but I felt that once I explained his motivation, he’d be forgiven quickly and not held accountable.
    “It’s about the cake and soda,” I said. “I know why you didn’t find any at the scene.”
    I spread out the timeline, which included what I knew of my students’ visits, without naming them. To my chagrin, Archie had had no call from anyone at Henley since his initial interrogation. I wondered about the legitimacy of marking the three applied statistics students down a grade for their cowardice. I was most disappointed in Rachel, over whom I had no grading power. Not that I would ever do such a thing.
    I oriented the timeline so Archie could read it. I’d marked the events of the day and laid them out in a straight horizontal line. “I’ve been over this a million times,” I said, breaking my rule never to exaggerate with numbers. “This is what I have.”
    Ten A.M., Woody hangs Keith’s award on his office wall.
    Eleven forty-five A.M., Woody sees Keith’s car in the lot.
    Twelve fifteen P.M., Franklin Hall party begins.
    One forty-five P.M., Rachel finds Keith dead, sees no yellow sheets, leaves cake and soda outside door. Two thirty P.M., Three girls arrive, see Keith dead, see cake and soda outside, no yellow sheets.
    Four P.M., Woody arrives, calls police, removes cake and soda from office, sees yellow sheets.
    Four ten P.M., police arrive, see no cake or soda, but do see yellow sheets.
     
    I indicated the place on the line between two thirty when the cake and soda were still outside the office, and four P.M., when the police found yellow pages, allegedly of Rachel’s thesis.
    “Here’s where the killer came back,” I said. “To incriminate Rachel, he went back and planted the cake inside the office and threw pages from Rachel’s thesis around, except Woody messed things up by trashing the cake. It’s the only thing that makes sense.”
    Archie stroked his chin while his head bobbed comically.
    “The killer came back and messed with his own crime scene,” Archie said. “Busy guy.”
    Archie picked up my timeline and held it close to his face, studying it. “So you’re saying the killer was essentially hanging around the crime scene waiting to plant evidence. I’m assuming you think he also planted the chemicals from the cabinet so it would point to Rachel, who had a key.” I nodded. “Why didn’t he just drop everything at once? Why risk going back?”
    “Well, there was no cake and soda until Rachel took it upstairs. That gave the killer the idea. And then I guess throwing the marked-up yellow pages in was just an afterthought. Overkill. So to speak.”
    “So the killer was at the party and saw Rachel head up to deliver the cake and soda and decided to take advantage of the situation. The overkill. Where’d he get the yellow pages?”
    I felt my face flush. My eyes suddenly itched. All along, I’d suspected the killer was one of the attendees at the Franklin Hall party, but that had been theory. Now the fact seemed to emerge from the timeline and the logic of the movements on Friday afternoon. The killer saw Rachel leave the room with the cake and soda. The killer had access to draft pages of Rachel’s thesis. I saw draft sheets in the trash around Franklin all the time, though something was different about those sheets compared to the way Virgil had described the ones at the crime scene. I wished I could remember his exact words. No matter, the point was that the killer could have picked them out of the trash any day of the week, if he was part of the Franklin family.
    I didn’t like my theory so much anymore.
    Apparently Archie did.
    “Nice