"Can you source any of it?" Sellitto asked.

"Generic fuse—untraceable—and the squib's destroyed. No manufacturer, nothing."

Cooper shook his head. All that was left, Rhyme could see, were tiny shreds of paper with a burned metal core of fuse attached. The strings turned out to be narrow-gauge 100-percent cotton, generic and thus also impossible to source.

"There was that flash too," Sachs said, looking over her notes. "When the officers saw him with the victim he held up his hand and there was a brilliant light. Like a flare. It blinded both of them."

"Any trace?"

"None that I could find. They said it just dissolved in the air."

Okay, Lon, you said it: bizarre.

"Let's move on. Footprints?"

Cooper pulled up the NYPD database on shoe-tread prints, a digitized version of the hard-copy file Rhyme had compiled when he'd been head of NYPD forensics.

After a few minutes of perusal he said, "Shoes are slip-on black Ecco brand. Appear to be a size ten."

"Trace evidence?" Rhyme asked.

Sachs picked several plastic bags out of a milk crate. Inside were strips of adhesive tape, torn off the trace pick-up roller. "These're from where he walked and next to the body."

Cooper took the plastic bags and extracted the adhesive tape rectangles, one by one, over separate examining trays, to avoid cross-contamination. Most of the trace adhering to the squares was dust that matched Sachs's control samples, meaning that its source was neither the perp nor the victim but was found naturally at the crime scene. But on several of the pieces of tape were some fibers that Sachs had found only in places where the perp had walked or on objects that he'd touched.

"Scope 'em."

The tech lifted them off with a pair of tweezers and mounted them on slides. He put them under the stereo-binocular microscope—the preferred instrument for analyzing fibers—and then hit a button. The image he was looking at through the eyepiece popped onto the large flat-screen computer monitor for everyone to see.

The fibers appeared as thick strands, grayish in color.

Fibers are important forensic clues because they're common, they virtually leap from one source to another and they can be easily classified. They fall into two categories: natural and man-made. Rhyme noted immediately that these weren't viscous rayon or polymer-based and therefore had to be natural.

"But what kind specifically?" Mel Cooper wondered aloud.

"Look at the cell structure. I'm betting it's excremental."

"Whatsat?" Sellitto asked. "Excrement? Like shit?"

"Excrement, like silk. It comes from the digestive tract of worms. Dyed gray. Processed to a matte finish. What's on the other slides, Mel?"

He ran these through the scope too and found they were identical fibers.

"Was the perp wearing gray?"

"No," Sellitto reported.

"The vic wasn't either," Sachs said.

More mysteries.

"Ah," Cooper said, peering into the eyepiece, "might have a hair here."

On the screen a long strand of brown hair came into focus.

"Human hair," Rhyme called out, noting hundreds of scales. An animal hair would have at most dozens. "But it's fake."