Pritchard had us climb into his truck. A black Malinois shepherd paced behind a screen in the back of it.

“My boy Samba back there’s an asset to you,” Pritchard said. “Best man-tracker in the state, and that’s no BS. Won down to Houston, fair and square.”

Mahoney said, “You don’t think they’ve left the county by now?”

“Probably so,” the Texas Ranger said. “But at least Samba can tell us the way they went and where your forensics team should focus.”

It made sense to me. Pritchard drove a ranch road to the base of the bluff. We got out and climbed a rocky, sandy wall through sage and other desert plants blooming.

It smells too good for a murder scene, I thought as we crested the rise. Mahoney puffed up beside me, with the Texas Ranger, his dog, and the FBI forensics crew trailing.

Pritchard adjusted his belt and then released the Malinois. “Seek, Samba. Seek!”

The dog’s ears went up. He bounded forward, arcing across the wind with his tail up. We watched him dodge sage plants and then slow, his muzzle raised and his nostrils flaring. I didn’t know dogs that well, but he seemed confused.

“Seek!” Pritchard said again.

The Malinois’s vigor renewed. He trotted forward again some forty yards, looking confident, then looped back toward us. His tail was all we could see for a few moments, wagging there above the brush.

Samba halted. He started to wheeze, then whimper, then shriek in pain. He exploded away from the spot and spun in circles, digging frantically at his nose and muzzle with his paws.

“Damn it!” Pritchard said, running after the dog. “He get into a porcupine?”

When the Ranger caught up to Samba, the dog was still crying and scratching at his face.

“Damn it,” the Ranger said again. “No quills,” he called back to us. “They must have sprayed the place with bleach or cayenne or both!”

I held up a hand, telling the forensics team to stay put. Mahoney and I donned blue booties. Ten feet apart, we walked abreast, searching the undergrowth separating us from Pritchard and his dog, which was still whimpering.

“I got something,” Mahoney said just as my eyes came to rest on a rectangular box lying in the sand.

“I do too,” I said, easing around a bush and putting on latex gloves.

I squatted down and picked up the box, which was about the size of a paperback novel. It had slits on the front, a fan on the bottom, a complicated control panel, and a logo.

“Anyone know what an Ozonics is?” I asked.

Pritchard had calmed his dog and reclipped his lead. “Portable ozone machine,” he said. “Hunters use them to kill odor. Makes sense.”

“Why’s that?” I asked.

“Wind’s blowing from us to the hacienda,” the Texas Ranger said. “If the ranch dogs had smelled them out here, they’d have barked, probably come to investigate. Sumbitches really thought this through, you know. Contingencies.”

Before I could agree, Mahoney held up a smaller, thinner metal box. “Any idea on this one, Mr. Pritchard?”

He told his dog to stay and came over to look. After several moments, he looked over at one of his deputies.

“Got your radio, Devin?”

The deputy nodded.

“Call me.”

He did, but Pritchard didn’t get the transmission on his end.

“Jammer,” the Ranger said. “No wonder the satellite phone wasn’t working.”

Mahoney said, “Looks like the ground’s been swept for a ways,” he said.

“Samba good enough to pick up scent back there?” I asked.

Pritchard shook his head. “His nose is toast for today.”

Mahoney said, “You know this country?”

The Ranger nodded. “Lot of it.”

“Where would their natural line of travel be? How would they likely go if they were heading, say, roughly north?”

Pritchard thought a moment. “Straight north, there’s a whole lot of nothing but BLM land, broken country, and box canyons for twenty miles, maybe more.”

“Northeast? Northwest?”

The Texas Ranger thought about that, then said, “Northeast, maybe four, five miles, there used to be an old road into a mining claim on the federal land, but I want to say its gated or blocked.”

“I’m betting it’s not anymore,” I said. “How long to drive there?”

“We’ll have to loop all the way around. Forty minutes?”

“We’ll fly,” Mahoney said.

We did. Following Pritchard’s directions, the helicopter took us to a heavy-duty gate off a spur of a country road. A sign said ROAD CLOSED. BUREAU OF LAND MANAGEMENT. The lock had been cut. We opened the gate and started on foot up a terrible, washed-out rock-and-sand road.

“No tire tracks,” Ned said.

“But look at all the little lines in the sand,” I said, kneeling. “It’s like whoever drove in and out was pulling brooms behind them.”

“Special Agent Mahoney?” the copter pilot called from the other side of the gate. “We just got the call, sir. President Hobbs is dead.”