“All right, so no known enemies,” Shelley said, nodding encouragingly even though she felt frustrated by the answer. It was always better to have somewhere to go next. “Through his whole career, do you think? He never had any trouble at all?”
Mrs. Henderson sniffed, shrugging her shoulders up and down. “Well, there was always something small,” she said, though her tone indicated she thought it could not possibly mean anything. “He was a professor. There were students who didn’t agree with their grades. Or those who flunked out for not attending class or turning in their work on time. They all think they ought to be given special treatment. But that’s normal. Just part of the job. No one would kill over something like a grade, would they?”
Shelley could see that Mrs. Henderson was really asking the question—looking for reassurance. Sadly, Shelley knew that she could not give it to her. People killed for all kinds of reasons. There was not always rationality behind it. Sometimes it was simply the final straw that made them snap, on top of everything else.
Maybe it was an idea worth exploring. Rich, entitled kid given everything in life, suddenly starts to fail for the first time? Throws a fit driven by privilege? Or some down and out student with nothing left to live for—parents recently deceased, girlfriend broken up with him, lost his part-time job, and then a bad grade on top of all the rest? It was something to look into, at the very least.
“Let’s hope not,” she volunteered, along with a small smile intended to convey her sympathies. “Can you think of anything unusual that might have happened in the past days or weeks—even months?”
Mrs. Henderson shook her head, dabbing at her eyes again. “I’ve thought about it, over and over. Everything was just—normal. That’s why it was such a shock. Totally out of the blue. I don’t know why anyone would want to hurt my Ralph at all.”
The woman was getting more and more distressed. Perhaps it would be prudent to wrap the interview up, leave her to her peace. “Is there anything else you can tell us—anything at all? It might not even seem relevant, but every little bit of information is another piece of the puzzle.”
Mrs. Henderson shook her head helplessly.
“All right, one last question. Do you recall your husband ever talking about a student named Cole Davidson?”
“Not until his name was in the papers,” Mrs. Henderson said. “That poor boy. Do you… do you think they are connected? They must be, mustn’t they? Two murders within such a short space of time?”
“It’s not useful for us to speculate at this stage.” Shelley took a final gulp of her coffee, regretting the need to leave behind half of what had been a very decent cup. “But we’ll be in touch if we can tell you more.”
Shelley stood, then hesitated as Zoe joined her. “Mrs. Henderson, do you have someone to keep you company today?”
She nodded slowly, getting up to escort them to the door. “My daughter is flying home. She should be here by tonight.”
That put Shelley’s heart at ease. Leaving a woman alone with her grief never quite sat right, no matter how many family interviews she did. “Then we’ll be in touch, Mrs. Henderson. In the meantime, try to get some rest.”
They got back into the car, Zoe pulling out her notebook immediately to start scribbling again. Shelley wondered if she had even heard a word of the interview, or if she had immediately dismissed it as useless and spent the entire time thinking about numbers.
Whichever it was, Shelley couldn’t get mad. Right now, the equations were the only real clues they had. As they drove back to base, Shelley couldn’t help but worry that they would not find anything of more value that would break the case open. With Zoe so fixated on the numbers, it was going to be up to Shelley to find something else that would make a difference.
The problem was figuring out where to look.
CHAPTER SIX
Zoe resented every moment of wasted time spent on the walk through the building, from the parking lot to the room they had taken over for their investigation. Nearly five hundred steps of distance that could have been spent on working. Nice as it was to be working on something that had happened, as Shelley put it, in their own backyard, Zoe was already getting irritable. The equations were refusing to give up their secrets to her, remaining obtuse and opaque.
As soon as she reached the table, Zoe sat down and resumed her notes, trying to work through every element of the professor’s equation, bit by bit. His was the one they had seen in person, after all, the one that they could be sure was whole.
“I’m going to go through his faculty email account,” Shelley announced, dumping her bag onto a chair and digging out her phone.
“Is that necessary?” Zoe asked, wrinkling her nose. There was no point in rushing around after some kind of clue like that. The answer was in the equations, not in the professor’s personal life. It had to be. There was no link between Cole Davidson and this English professor, not without the equations.
“I’m not good at math, so I can’t help you work through the numbers on this one,” Shelley pointed out. “Something Mrs. Henderson said made me think. It could always be something to do with a student. Someone who felt slighted in some way. It’s possible that there are many people who knew both Cole and Professor Henderson from campus.”
Zoe hesitated, her objections waiting on the tip of her tongue. She felt like it would be a waste of time, poking through a dead man’s emails. But what did it matter? Shelley was right—she couldn’t help with the equations. And maybe it was time that Zoe started trusting her to investigate things in her own way.
Maybe, also, it would be good for Zoe if this case was solved off the back of a disgruntled email, rather than through the numbers. After Shelley had pointed out to their superiors that Zoe was good with math, Zoe wasn’t exactly at pains to prove it. In fact, it would be better if she could pass that off as a partner’s misplaced confidence.
But not, of course, if it compromised the case. Stopping the killer was still the most important thing.
Zoe returned her attention to the equations while Shelley called the university to get the access she needed. The thing was, she had gone about as far as she could go—with both of them. It was true that there was still the possibility of something missed on the student’s body, but they had checked the professor for themselves.
So, what was she missing?
There was another possibility, of course: that she simply wasn’t advanced enough to solve it. There was a difference between being able to see numbers—distances, dimensions, angles—and being able to solve quantum math problems. There were other skills involved, skills that other people spent their whole lives developing. Zoe might have had a gift, but she had devoted it to the pursuit of killers, not to the study of math.
Which brought another idea to her mind.
She got up, leaving Shelley still chatting with a receptionist on her cell, and carried a sheaf of photographs down the hall to the elevator. Up two floors, and down an identical corridor to the one she had left—except that the rooms on this floor had rather more power exuding from each of them.
Zoe took a breath before knocking on her boss’s door. How many times had she been summoned here, to be chewed out for losing another partner or discharging her firearm?
But this was not like those times, and she entered when bidden, trying not to feel nervous.