“So?”

“It’s a white, odorless compound that resembles salt. Or sweetener. And it dissolves readily in liquids.”

Joanna felt her pulse quicken. “I suppose it’s also poisonous?” she asked.

“Very,” Dave agreed. “More poisonous than cyanide.”

“And tasteless?”

“I wouldn’t know about that,” Dave answered. “And I don’t know how you’d find out for sure. Who’d be willing to taste it, and how would they tell us what they’d found out after they died? But since it evidently ended up in Rochelle Baxter’s iced tea and since she emptied the glass without noticing, we pretty much have to assume it’s tasteless.”

“If sodium azide is that deadly, how come she didn’t die right away?”

“Ingested poisons don’t work until they’re assimilated into the bloodstream. If you breathe it in, it can kill almost instantly. I’m lucky I just got woozy when I did. Otherwise, you’d be having another Fallen Officer funeral in a day or two,” Dave went on.

“Thank God,” Joanna said. “But tell me, where would somebody get this awful stuff?”

“That’s the really bad news,” Dave Hollicker replied. “The answer is, almost anywhere. It’s not a controlled substance, so you could buy a whole barrel of it if you wanted. You could also rip the air bags out of your car and claim somebody stole them. Or else you could go to your local junkyard. If a car wrecks and the air bags are deployed, it’s not a problem. Once the air bag inflates, what’s left after the sodium azide oxidizes is totally harmless. It’s the undeployed air bags with their canisters of unused sodium azide that are the problem.”

“Don’t junkyards strip the air bags out and sell them?” Joanna objected. “My understanding is that they can be parted out and reused.”

“That’s how everybody assumed it would work,” Dave said. “In actual practice, it’s not that simple. People don’t want to ride around in a vehicle where their life and the lives of their loved ones depend on the effectiveness of somebody else’s secondhand air bag. And, if death or injury occurs in a vehicle fitted with a used air bag, there’s always a potential liability problem. All of which leaves this country with millions of unrecycled air bags sitting in junkyards everywhere.”

“The sodium azide is loose, then?” Joanna asked.

“No. It comes in little aluminum canisters about the size of tuna-fish cans. I’m guessing there are stacks of dozens of those little hummers sitting on used-parts shelves in junkyards in Cochise County alone.”

“Wait a minute,” Joanna objected. “You’ve told me this is a deadly poison. Do you mean somebody could just walk in off the street and pick a can of it off a shelf?”

“You ever been to a junkyard, boss?” Dave Hollicker asked.

“Not recently.”

“Well, that’s pretty much how they work. Around here, junkyards are long on self-service.”

“Can sodium azide be traced?”

“You mean have the manufacturers put markers in it the way they do with explosives?”

“Exactly.”

“I suppose it’s possible, but I’m guessing the automobile industry would be dead-set against it.”

“Because they don’t want to admit the stuff is a potential problem?”

“You’ve got it,” Dave agreed.

“Great,” Joanna said. “It’s readily available, totally untraceable, and deadly.”

“And that’s what was in those tampered sweetener packets that Casey and I brought back from Latisha Wall’s place down in Naco. I’ve got the DPS crime lab’s printed analysis right here in my hand.”

“Have you told anyone else about this?” Joanna asked.

“Not yet. I’ve been cooling my heels around here all day waiting for test results. They dissolved some and ran it through an ion chromatograph. That’s what I have right now – a preliminary report and a tentative identification of sodium azide. They’ll do a confirmation test using mass spectrometry. The lab manager told me we won’t have tentative results on that for another day or so. Official results will take another week. The criminalist I talked to says they can use the same technique on vomit samples if Doc Winfield sends them along, but that takes up to two weeks longer. I thought you should be the first to know.”

“Thanks for calling,” Joanna said. “I’ll get on the horn and tell everyone else.”

“Do you want me to come by the office with this when I get back to Bisbee, or can it wait until tomorrow?”

Joanna thought about the board of supervisors meeting and the looming overtime issue. “No, since it’s just a preliminary copy, have the lab fax one to the department tonight. Nobody will be able to work on it before tomorrow or Monday anyway. Good work, Dave,” she added. “You and Casey deserve a lot of credit for being on top of this.”

“Thanks, boss,” he said, “but isn’t that what you pay us to do?”

Joanna heard the unmistakable pleasure in his voice at having been given a compliment. “You’re right,” she returned. “That’s exactly why we pay you the big bucks.”

By the time she hung up, Butch had gone over to the fridge and pulled out a beer. “I can hear it already,” he said. “They’re sucking you back into work, aren’t they?”

“Not really,” Joanna said. “But now that we know what killed Rochelle Baxter, I have to tell people. I’ll make some calls. It won’t take more than a few minutes.”

She went into the living room. Butch, tired of having the dining-room table constantly littered with work-related papers, had redesigned the living room. Eva Lou Brady’s little fifties-era telephone table had been replaced by a secondhand cherry secretary, where Joanna’s papers could be spread out and the hinged desk surface closed up over them when necessary.

Joanna retreated there and picked up the phone. The first call she made was to Jaime Carbajal.

When Jaime’s wife, Delcia, said, “Hold on, I’ll get him,” Joanna glanced guiltily at her watch. It was only a few minutes past four. Good, she thought. At least it’s too early for me to be interrupting dinner.

When Jaime came to the phone, he sounded out of breath. “Pepe and I were out doing batting practice,” he said. “Frank told me earlier about Sadie. Is Jenny okay?”

“She’s fine,” Joanna returned. “In fact, she’s handling it better than I am at this point, but tell me about the interview with Bobo Jenkins. How did it go?”

“No surprises there,” Jaime said. “Bobo insists he had nothing to do with what happened to Latisha Wall. He claims the two of them were in love and that he had no reason to harm her.”

“Did he mention being afraid that she was about to break up with him?”

“He said something about it, but he claimed things were fine between them when he left her place on Wednesday night. As far as I’m concerned, that remains to be seen.”

“Did you let him know we found his prints on the sweetener packets?”

“No. That’s a holdback. I didn’t want to say anything about that until I had a chance to talk to both Dave and Casey.”

“Makes sense,” Joanna said.

“Did you ask Bobo about Dee Canfield?”

“Affirmative. He claims the last time he saw her was in the gallery on Thursday morning. He said you were there at the same time. He says he has no idea what happened to her afterward, and he has no clue where she and Warren might have gone.”

“He’s right,” Joanna said. “I was there when he was. Now what’s the deal on the search warrant?”

“Not yet,” Jaime said. “I finally found out why the judge didn’t come home last night. Mrs. Moore ended up in TMC with an emergency appendectomy. I talked to their house sitter. She says Judge Moore is supposedly coming back to Bisbee tonight. The soonest I’ll be able to get the warrant and serve it will be later this evening.”

“That’ll have to do, then,” Joanna said. “If you want someone along when you serve it, check with Frank.”

“Will do,” Jaime said. “Now, what about Dave Hollicker?”

The detective listened in silence while Joanna told him what the crime scene investigator had learned. “Does Frank know about any of this?” Detective Carbajal asked.