“If Peter didn’t find anything in her stomach contents, I can’t imagine what it could be,” Laurie said. “But did you consider methemoglobinemia?”

“No, but isn’t that rather rare?” Methemoglobinemia was a condition where the hemoglobin was rendered incapable of carrying oxygen.

“Well, you’re asking me for something that causes cyanosis,” Laurie said. “You should at least consider the nitrates and nitrites which can cause methemoglobinemia. Even the sulfonamides.”

“But wouldn’t that only be with someone who was congenitally susceptible?” Jack asked.

“Probably in relation to the sulfonamides,” Laurie said. “But not necessarily with the nitrates and nitrites. Still, if you want to be complete, you have to consider it.”

“Okay, you’re right,” Jack said. “I’ll ask Peter to assay for them in the morning. Anything else?”

Laurie thought for a few more minutes, but then shook her head.

“There’s one more twist to this story,” Jack said. He then went on to tell Laurie about the rat die-off in the same Brooklyn neighborhood where Connie Davydov had lived.

“Do you think there’s an association?”

Jack shrugged. “Your guess is as good as mine, but it is a curious coincidence.” He told Laurie that Connie apparently lived in an old cottage in an enclave of similar buildings. He mentioned his idea about the plumbing being primitive.

“Seems like a far-fetched connection to me. If something deadly leaked up from the sewer, why would it only be in one house?”

“You got me,” Jack admitted. “But let’s go on to my other mystery.” Next, Jack told Laurie about Ted’s further analysis of the tiny glittering star. “It’s as if the star were made of flypaper and dropped into a bowl of anthrax spores.”

“Why is it that you get all the interesting cases?” Laurie teased.

“Come on!” Jack said. “I’m serious. Can you explain it? Remember, I cultured all around the star, including the blotter it was sitting on and the desk itself. The PCR test is so sensitive it can detect as little as just a few spores. Everything was clean.”

“You’ve stumped me again,” Laurie said. She glanced at her watch. “Wow! It’s after midnight, and I’m keeping us both up.” She got to her feet.

“Are you going to be okay?” Jack asked. “You’re welcome to stay here. You can have the bed. Half the time I fall asleep out here on the couch anyway.”

“Thanks for the offer,” Laurie said. “You’ve been very hospitable, but I really should go home. I don’t have clothes for tomorrow or anything else.”

“It’s your call,” Jack said. “You’re more than welcome. But if you do go, at least promise me you’ll give me a buzz when you get home. It’s late to be wandering around even your neighborhood.”

“Will do,” Laurie said. She gave Jack a sustained hug.