The Square Root of Murder (Professor Sophie Knowles)

leader Pam Noonan, and others who frequented Franklin Hall on a regular basis.
    Until we came to the samples from the newly anointed Dr. Hal Bartholomew. Virgil and I agreed that of all the samples, Hal’s was closest to the markings on the sheets strewn over the crime scene. Besides the overall appearance and slant to the letters, Hal’s strangely curved capital A on his postcard with “All’s well in Bermuda” looked like a perfect match to the A in “Awful Data,” written on Rachel’s thesis. This, combined with a couple of other unique strokes, caused us to set aside Hal’s samples and create a new pile. When we’d gone through every card and note, Hal’s were the only samples in the pile.
    “Don’t get your hopes up,” Virgil said. “Neither of us is a professional, and we might be way off base.”
    I wasn’t exactly hoping that Hal was a killer. What had I been thinking anyway, isolating all my friends as potential murderers? Now that it seemed one of them might actually be guilty, I was devastated.
    I forced myself to skip past the high probability that Hal might have killed Keith. Whatever it meant, I was more than ready to see an end to the investigation. No matter what Virgil had said about how long he spent on a murder investigation in Boston, four days were enough for me.
    Hal’s motives were legion. Over the years, Keith had ridiculed him, voted against a bonus for him, and challenged his eligibility to take a turn as physics department chair, to name a few affronts. Even Hal’s glee over receiving his doctorate was sullied because of Keith’s constant reminder of how many times Hal had had to redo the experiments his dissertation was based on.
    I breathed a long, heavy sigh. “What’s next?” I asked Virgil. I meant “for Hal.”
    “I’ll get our expert to look at this. I don’t see any reason to give him the whole bag, but I’ll pick a couple out of the pile and add them, just as a kind of control.”
    “It sounds very scientific,” I said.
    “Don’t tell anyone, okay?”
    “I’d never want to spoil your image.”
     
     
    I stuffed all the “no” votes back in the grocery bag and headed out to my Fusion. I turned on the A/C and sat for a couple of minutes with my phone, checking emails and messages. The most exciting news was a “thumbs up” text from Bruce about his medical tests. I texted back, “Good 4 U. CU.”
    On par with that was a text from Rachel: “Home again. THX.” Maybe the handwriting angle convinced Virgil who convinced Archie that Rachel was innocent. I was tempted to call and say THX to Virgil, too, but I didn’t want to be presumptuous. I did keep my phone on in case he called me with his expert’s results. I wondered if the turnaround time for handwriting analysis was as long as Virgil claimed it was for fingerprints and DNA evidence.
    I hoped both Rachel and I had seen the last of the Henley police building.
    Hal Bartholomew’s handwriting seemed to be scrawled across the heavy, humid sky over Henley, Massachusetts. I couldn’t imagine the mild-mannered physics teacher planning out a murder. And it was clear that Keith’s murder was not a spontaneous crime of passion. You didn’t just happen to have a needle with a lethal dose of poison in your pocket and use it in a moment of anger.
    I thought of Hal’s family—hard-working Gillian and five-year-old Timmy, who adored his father—and the effect Hal’s conviction would have on them.
    Maybe I was jumping the gun. I secretly hoped our amateur handwriting analysis was way off, like a data point on a graph that misses the average curve by orders of magnitude. It would mean back to square one, however, which might be where Rachel was standing. It seemed a no-win situation.
    A few more minutes and I’d have been able to convince myself that the handwriting expert would tell Virgil he’d never seen a poorer match in all his years of experience. I stopped short of thinking what that would mean for Rachel or for finding the real killer.
    What to do next?
    With the afternoon free for research, a good mathematician would immerse herself immediately in her field. Follow-up papers weren’t expected sooner than eight to nine months apart, but even that schedule required steady application to the work. I told myself I could afford a short break, having mailed my latest differential equations paper so recently. And what better way to keep research skills sharp than to comb through decades-old