Professor Walker, what do you think?”
Stunned, Christopher could only stare at him. “What?”
“My ME tells me the numbers should have been switched. That the concentration in the cup should have been higher. That the poison in the coffee should have been diluted in his stomach.”
Nate shook his head. Hard. “No way. That has to be a mistake. It has to be.”
“My ME thought so, too. So he reran the test. Twice more. Had a colleague do the same. The numbers were consistent with every test.”
Tanya was pale. “Your equipment . . . maybe it needs to be calibrated.”
Harris regarded her with a level stare. “It’s a police crime lab, Miss Meyer,” he said dryly and Christopher got the impression that while Tanya hadn’t pissed him off before, she’d done so now. “Our equipment is every bit as sophisticated as yours.”
Christopher pulled the heels of his hands down his face, his stomach churning once more at what the detective had left unsaid. “Wait. You’re saying it wasn’t an accident? That Darrell did this to himself? That’s as impossible to believe today as it was on Friday. Darrell Roberts would never have taken his own life.”
Harris just looked at him. “I agree, Professor.”
For a moment, Christopher just looked back. Then cognition hit and he could feel the color draining from his face. “Oh, my God. You’re saying somebody else did this? That somebody murdered him? That’s . . .” He dropped into the chair behind his desk. Searched the faces of his students. All three looked as sick as he felt.
Harris’s face didn’t change, not a muscle moved. “We found Darrell’s fingerprints on the cup, but no trace of his DNA on the cup.”
“Maybe he wiped it off.” Tanya’s whisper was thin.
Harris’s smile was sardonic. “There was no trace of DNA in the coffee left behind, either. We didn’t find any trace of a straw near his body, either, so don’t even try. What do you conclude from this, Professor?”
Christopher met Harris’s gaze unwaveringly. Made himself remain calm at the implied accusation. It’s a police technique, he thought.
But I have nothing to hide
. “I’d have to say the cyanide was introduced from two different sources, Detective. But while this seems to rule out accidental ingestion, it doesn’t definitively prove foul play.”
“Spoken like a lawyer,” Harris observed. “Not a chemist.”
“I watch TV,” Christopher replied evenly, then clenched his jaw. “Look, Harris, I still can’t believe Darrell would kill himself, but if somebody killed him, that person would have to have access to this lab. And that’s us. So if that’s the direction you’re going, just spit it out.”
Harris didn’t blink. “All right. So where were you between ten p.m. Thursday night and one a.m. Friday morning, Professor?”
Nate covered his face with his hands. “This isn’t happening,” he whispered.
Christopher let out a controlled breath. Commanded his heart to slow down. “I was home with my daughter, Megan. She went to bed at ten thirty. I called my mother at eleven thirty. I imagine you can check my phone records to confirm this.”
“Kind of late to be calling your mother, isn’t it?”
“She lives in California. It was only eight thirty there.”
Harris nodded, took out his notebook and jotted it all down. “All right. Any way to prove where you were between midnight and one?”
“No. I’m divorced, so I have no wife to verify my alibi.” And Mona wouldn’t have if she had been there, Christopher thought grimly. “I did do some research on the University’s online library between twelve and one. The server records should verify it.”
Harris turned to Tanya. “And you, Miss Meyer?”
Tanya was white-faced and trembling. “I was home sick. My aunt can tell you.”
“Your aunt was awake all night?”
“She came in once, when I was throwing up in the bathroom. I don’t know exactly what time it was, but it was before