She didn’t take umbrage. “I found what appears to be a fragment of plastic wrap on the inside of her right index fingernail, with a corresponding blanching of the nail itself, consistent with it having been stressed through a levering or scratching motion.”

Both men considered that before Joe responded, “Wrap or a bag?”

“Bag, I think. It was thicker than what ‘wrap’ implies.”

“You think she was suffocated?” Willy asked.

“I do not. Not on the evidence. But she may have been.”

Willy pressed on. “A bag was put over her head?”

“Perhaps.”

“And she clawed to tear it off.”

Beverly didn’t answer.

“Wouldn’t there be something more? A scratch on her own face, like when people try to get the rope off their neck when they’re being strangled? They claw like crazy.”

Joe followed a different tack by asking, “How would that work? Could someone do it while she was sleeping?”

“Her blood alcohol content was very high,” she told them. “I don’t know how heavily she drank on a daily basis. Her liver is that of an alcoholic. But it’s conceivable she was in a stupor when this happened, if it did.”

“So, someone might’ve gotten her into that state, or she did it on her own beforehand.”

“Good luck proving that,” Willy muttered.

“There is another possibility,” Beverly suggested.

It was rare for her to entertain hypotheticals, so Joe was keen to hear this. “Go on.”

“There is sound documentation about the use of inert gases in these instances. The circumstances almost always concern suicides, but I don’t know why it couldn’t work in a different scenario. The pathologist would have to be aware of such a mechanism before autopsy. Otherwise, she wouldn’t enact the special procedure needed to extract the gas before it dissipated. And even then, after that small time window is closed, there’s no longer any evidence to be had.”

“Inert gas?” Willy asked. “What’s that mean, exactly?”

“It could be nitrous oxide,” she ventured. “Laughing gas. Or helium. Even simpler. You can rent a bottle of it at any balloon store for a birthday party. What I’m suggesting is that someone could place a bag loosely over a sleeping person’s head or face before introducing the gas into what’s now a largely closed environment. I suspect that a heavily inebriated victim might not even notice.”

“Except for one feeble scratch at the bag before dying,” Joe suggested.

“Correct,” she agreed before adding—pure Beverly—“Keep in mind, this is all purely theoretical.”

“For you, maybe,” Willy said. “But I can work with this.”

“You are thinking what I am, aren’t you?” Willy asked later.

Joe was driving this time, returning to Brattleboro. “About Shaw’s alibi?” He weighed his response before continuing, “Instinctively, yes. I think he’s dirty. More globally? We have some hurdles to jump before we can put him on the spot, beginning with the fact that we don’t have a homicide with Lucy Shaw. We don’t even have an undetermined. You know as well as I do that her tox’ll come back six weeks from now with no more than booze and some therapeutic levels of prescription meds. If somebody was clever enough to knock her off without leaving evidence, it’s unlikely a bolus of arsenic will suddenly show up at the end. Beverly’s going to be stuck with a ruling of natural death.”