"Well, Bullard's on another level. He's crude, too, but highly intelligent. I wouldn't underestimate him. The fact is they both know a lot more about Grove's death than they're telling. We can crack Cutforth, I'm pretty sure-he's a wuss-but Bullard's going to be a tough nut."

Pendergast nodded. "The forensic report on Grove's body should be ready tomorrow. That may give us badly needed information. The critical thing now is to find the connection between Bullard, Cutforth, and Grove. If we find that connection, Vincent, we'll have the key to this entire mystery."

{ 17 }

Dr. Jack Dienphong cast his eye about his laboratory: examining the metal tables, the chemical hoods and glove boxes, microscopes, SEMs, microtomes, and titration setups. It wasn't pretty, but it was organized and functional. Dienphong was chief of the FBI's Forensic Science Division on Congress Street, and he was very curious to meet-at last-this Special Agent Pendergast he had heard so much about.

He glanced down at the scribbled index card in his hand, running through his notes one more time. Most of it was in his head: the index card was more for comfort than anything else. He felt a disquieting sense of apprehension. He didn't like what he was going to have to report, and he just hoped the famous-some said infamous-agent would understand. In Dienphong's opinion, the worst mistake one could make in forensic chemistry was to over interpret results. Do that enough times, and eventually you'd send an innocent man to prison. It was Dienphong's greatest fear. He wouldn't stretch results for anyone, not even someone as formidable as Pendergast.

There was a stir at the door, and Dienphong glanced at his watch. On time almost to the second, already confirming one thing he'd heard Pendergast was famous for. A moment later the door opened, and a slender man in a black suit entered, followed by Special Agent in Charge Carlton, chief of the Southern District Field Office, and a hushed group of junior agents and assistants. There was an almost palpable excitement in the air, the kind of excitement high-profile cases always generated. And only a high-profile case like this would bring somebody like Carlton in on a Sunday. All the pertinent evidence had been forwarded to the FBI by local police for in-depth analysis. And now it was up to Dienphong to piece everything together for them. His feeling of apprehension did not diminish.

Dienphong observed the stranger carefully. Pendergast was just as people had described him, moving with the efficiency and grace of a cat. His hair was so blond it was almost white, his face cool and patrician, his pale eyes restlessly taking in everything. Dienphong had met many FBI agents in his time, but this one was in another category altogether.

Those ice cool eyes alighted on Dienphong, and the agent came striding over. "Dr. Dienphong," the man said in the buttery tones of the Deep South.

"A pleasure." Dienphong took the dry hand.

"I thought your piece in the Journal of Forensics on the maturation rate of blowfly larvae in the human cadaver to be fine reading."

"Thank you." He hadn't quite thought of the article as "fine reading" himself, but then each to his own. Dienphong's idea of fine reading was Johnson’s Rambler essays.

"The presentation is all ready," he said, gesturing toward a double row of metal chairs set up before a projection screen. "We're going to begin with a brief visual presentation."

"Excellent."

The agents seated themselves with murmurs, coughing, and scraping of chairs. Special Agent in Charge Carlton took up position in the front row center, his thick thighs spilling off the edges of the seat.

Dienphong nodded toward his assistant and the lights dimmed. He switched on the computer projector.

"Please feel free to interrupt with questions at any time." He called up the first image. "We'll go from simplest to most complex. This is a 50x sample of the sulfur recovered at the site. Our chemical analysis showed it to be natural, with trace elements that indicate a volcanic origin. It had been rapidly heated and burned by unknown means. When sulfur burns, it combines with oxygen to make sulfur dioxide gas, SO2, which has a very strong odor-the smell of burned matches. If it then comes in contact with water, it creates H2SO4, also known as sulfuric acid.

"These fibers here" -the next image came up-"are from the victim's clothing. Note the pitting and curling: clear effects of sulfuric acid on the victim's clothes."

Three more images in quick succession. "As you can see, there was even microscopic pitting on the victim's plastic glasses, and in the varnish on the walls and floor, from the intense release of sulfur compounds."

"Any idea of the specific volcanic source?" It was Pendergast who spoke.

"That's almost impossible to answer. We'd have to analyze and compare this with thousands of known volcanic sources, an overwhelming job even if we could get the samples. What I can tell you is that the high proportion of silicon indicates a continental, as opposed to an oceanic, source. In other words, this sulfur didn't come from Hawaii or, say, the seafloor."

Pendergast settled back, his expression unreadable in the dark room.

"This next image shows some microsections of the burned wood of the floor from the so-called hoofprint." Several more images flashed across the screen. Dienphong cleared his throat. Here is where the difficulties began.

"You will note the very deep penetration of the burn into the wood. You can see it better at 200x."

Another slide. "This was not caused by a 'branding iron' effect." He paused, swallowed. "That is to say, this mark was not burned into the floor by a red-hot object being impressed into the wood. It was caused by an intense burst of no ionizing radiation, probably in the very short infrared wavelength range, which deeply penetrated the wood."

Carlton spoke up, as Dienphong knew he would. "You mean, the perp didn't heat something up and press it on the wood?"

"Exactly. Nothing actually touched the wood. The burn was made by a short blast of pure radiation."

Carlton shifted, the chair uttering a dangerous groan. "Wait a minute. How can that be?"

"My job is to describe, not interpret," said Dienphong, flicking up the next slide.

But the chief hadn't finished. "Are you saying the mark was made with some kind of ray gun ?"

"I can't say what the source of the radiation was."

Carlton settled back with a dubious grunt.

"This brings us to the cross." The next slide came up. "Our art expert has identified this as a rare example of a seventeenth-century Tuscan cross, commonly worn by the noble classes. It is made of gold and silver, layered, fused, and hand-chased to produce a rather interesting effect known as llamellés fines . It was then set in wood, which has largely burned away."

"How much's it worth?" Carlton said, asking an intelligent question for a change.

"Given the precious stones, eighty, perhaps one hundred thousand dollars. Undamaged, that is."

Carlton whistled.

"The cross was found around the neck of the victim, touching his skin. Here is a photograph of it at the scene of the crime, still around the victim's neck."

The next slide came up, prompting noises of disgust and disbelief.

"As you can see, the cross heated to the point of melting, deeply burning the skin where it lay. But observe that the surrounding flesh is not scorched or even reddened. Something-and I really can't say what-selectively heated the cross without heating the surrounding skin. The cross then partially melted and burned itself into the victim's flesh in situ.