I started a more serious search into scholarly articles about germ warfare. Much of the language was beyond me, but I gathered that the plague bacillus could be dried and sprayed over a targeted population, which made it possible to use Y. pestis as a weapon. Even though it was less stable than anthrax, it was so efficiently lethal that it remained a perennial favorite among germ warriors.

My eyes were dry and gritty. I turned off the light and lay back down, but I couldn’t turn off the feverish churning in my head.

How had Shirley Kiel described Chastain’s “colossal blunder”? He’d cultured the wrong specimen or switched specimens. Had he exchanged Dr. Kiel’s pet organism, Yersinia enterocolitica, for Y. pestis?

If that was what had happened, it was criminal sabotage, not a blunder. I didn’t know anything about Chastain, except that Sonia had been in love with him. I was guessing he was Cady Perec’s father because in Sonia’s youthful journal she’d recorded seeing him with Jennifer Perec, but I had to admit that was a leap. Gertrude and Kiel both thought he was a loser, but it was hard to believe Chastain would be so embittered by Kiel’s endless insults that he would have started working with the plague instead of the stomach bug.

“Maybe he was a clumsy SOB,” I said to Peppy, “but surely he wouldn’t knowingly have endangered Jenny Perec or baby Cady.”

I wondered about Sonia: she’d been a dishwasher in her father’s lab. She was lovesick, she was jealous of Jenny. But even if she’d been unstable enough to try to hurt Jenny, I couldn’t believe she would have known how to make a switch. You wouldn’t leave Y. pestis sitting around in an air-freshener can where random people could spray themselves with it.

Magda Spirova, though . . . Kiel’s sons thought she’d slept with their father when they met in Czechoslovakia. Say she came to Kansas expecting the affair to continue and instead found herself in a cauldron of Shirley’s fury and Kiel’s fears of exposure. She could have switched the bugs and then blamed Kiel’s whipping-boy student. After all, she’d worked at a bioweapons installation in eastern Czechoslovakia.

I sat up again and went back to the Douglas County Herald story on Magda Spirova. Těchonin. The Web revealed that this was a dot on the map, not even a thousand inhabitants. The Russians made it famous, or infamous: after they consolidated control of Eastern Europe, they’d set up a bioweapons research site there. Among other things, they built giant fermenters to produce cool things like anthrax and typhus in huge quantities. Then they dried the bugs and figured out how to spray them over civilian populations. Magda brought that knowledge with her to Kansas.