Bones Never Lie (Temperance Brennan, #17)(80)

“Doc.” Slidell’s way of announcing our arrival.

Larabee turned, thermometer in one gloved hand. Hawkins kept snapping away. “Detective Slidell. Dr. Brennan. Gotta love a brisk winter dawn.”

“What have we got?” Slidell opened his spiral.

“Probable carbon monoxide poisoning.”

“The guy offed himself?”

“The first responders found no signs of forced entry in the house or garage. No note. I’m seeing minimal trauma.”

“Minimal?”

“Abrasions on the forehead and right ear. Probably caused by the head impacting the wheel.”

“Probably?”

“Possibly.”

“Meaning suicide.”

“I’ll know after the autopsy.”

Most carbon monoxide deaths are due to accident or suicide. A few are due to foul play. Larabee knew and was being guarded.

“The garage door was down when Cauthern arrived?” Slidell asked.

“So I’m told.”

“The car hood wasn’t raised, right?”

“Right.”

“The vic have any grease on his hands?”

“No.”

Slidell scanned the small space where we stood. “No tools lying around.”

“I agree, Detective. This doesn’t look like an accident.”

“Time of death?”

“Based on body temp, I’d put it somewhere between twelve and two this morning. As usual, that’s only a rough estimate.”

“How long’s it take?”

“Death by carbon monoxide poisoning?”

Slidell nodded.

“Not long.”

Slidell frowned.

“It requires very little CO to produce lethal levels of carboxyhemoglobin in the body.”

The frown continued.

To his credit, Larabee showed no impatience. But he kept it simple. Very simple. “Carboxyhemoglobin disrupts oxygen supply to the cells.”

“Gimme a little more than that.”

“Okay.” Larabee did some editing. “Hemoglobin is a molecule found in the red blood cells. Its job is to circulate oxygen throughout the body. But hemoglobin has a strong affinity for carbon monoxide, CO. If both oxygen and carbon monoxide are present, hemoglobin is much more likely to bind with the CO. When that happens, you get carboxyhemoglobin, which can’t do the job.”

Larabee didn’t go into the fact that hemoglobin has four binding sites to maximize the capture of oxygen from arterial blood flowing from the lungs and to expedite its release into the tissues and organs. That in the presence of both oxygen and carbon monoxide, hemoglobin is two to three hundred times more likely to bind with the latter. That this binding with CO inhibits the release of O2 molecules found on the hemoglobin’s other binding sites. That, as a result, even if blood concentrations of oxygen rise, the O2 remains bound to the hemoglobin and isn’t delivered to the cells. That, as a consequence of oxygen deprivation, the heart goes into tachycardia, increasing the risk of angina, arrhythmia, and pulmonary edema. The brain short-circuits.

That carbon monoxide is very bad shit.

“We’re talking how much?” Slidell pressed.

“High blood levels of carboxyhemoglobin can result from air containing only small amounts of CO.”

“You breathe the stuff.”

“Yes.”

I was sure Slidell knew the basics, that he’d worked similar cases in the past. I wondered at his uncharacteristic interest in the physiology of carbon monoxide poisoning.

My brain fired a series of stats on CO blood levels. Of symptoms of toxicity. Bizarre. A stored holdover from some long-ago grad school course. 1 to 3 percent: normal. 7 to 10 percent: normal in smokers. 10 to 20 percent: headache, poor concentration. 30 to 40 percent: severe headache, nausea, vomiting, faintness, lethargy, elevated pulse and breathing rates. 40 to 60 percent: disorientation, weakness, loss of coordination. 60 percent: coma and death.

Slidell sighed. “How ’bout a ballpark?”

“Of?” Larabee had squatted to inspect Ajax’s hands.

“How long you last.”

“Inhaling air with a carbon monoxide level as low as point two percent can produce carboxyhemoglobin levels exceeding sixty percent in just thirty to forty-five minutes.”

“That’ll kill ya?”

“That’ll kill ya.”

Slidell jotted, then gestured with the spiral. “And we got that here?”

“Engine running in an enclosed one-car garage. Door lowered. Windows shut. Definitely.” Larabee spoke without looking up. “In as little as five to ten minutes.”

“So Ajax was toast soon after he turned the key.”

“Assuming he turned the key.”

“Assuming that.”

“And that he was breathing when he went into the car.”

“And that.”

“Which I suspect was the case. See this?” Larabee lifted one of Ajax’s hands.

Slidell eyeballed it from where he was standing. “That blood-settling thing. Because the arms are hanging down.”

“Yes. But I’m talking about the nail beds.”

Slidell bent for a closer look. “They’re bright pink.”