Rhyme strained forward, lost in the rainbow auras of refraction. "Looks like standard PPG single-strength window glass."
"Agreed," Cooper said, then observed, "No chipping. It was broken by a blunt object. His elbow maybe."
"Uh-huh, uh-huh. Look at the conchoidal, Mel."
When someone breaks a window the glass shatters in a series of conchoidal breaks--curved fracture lines. You can tell from the way they curve which direction the blow came from.
"I see it," the tech said. "Standard fractures."
"Look at the dirt," Rhyme said abruptly. "On the glass."
"See it. Rainwater deposits, mud, fuel residue."
"What side of the glass is the dirt on?" Rhyme asked impatiently. When he was running IRD, one of the complaints of the officers under him was that he acted like a schoolmarm. Rhyme considered it a compliment.
"It's . . . oh." Cooper caught on. "How can that be?"
"What?" Sachs asked.
Rhyme explained. The conchoidal fractures began on the clean side of the glass and ended on the dirty side. "He was inside when he broke the window."
"But he couldn't've been," Sachs protested. "The glass was inside the hangar. He--" She stopped and nodded. "You mean he broke it out, then scooped the glass up and threw it inside with the gravel. But why?"
"The gravel wasn't to prevent shoe prints. It was to fool us into thinking he broke in. But he was already inside the hangar and broke out. Interesting." The criminalist considered this for a moment, then shouted, "Check that trace. There any brass in it? Any brass with graphite on it?"
"A key," Sachs said. "You're thinking somebody gave him a key to get into the hangar."
"That's exactly what I'm thinking. Let's find out who owns or leases the hangar."
"I'll call," Sellitto said and flipped open his cell phone.
Cooper looked through the eyepiece of another microscope. He had it on high magnification. "Here we go," he said. "Lot of graphite and brass. What I'd guess is some 3-In-One oil too. So it was an old lock. He had to fiddle with it."
"Or?" Rhyme prompted. "Come on, think!"
"Or a new-made key!" Sachs blurted.
"Right! A sticky one. Good. Thom, the chart, please! Write: 'Access by key.' "
In his precise handwriting the aide wrote the words.
"Now, what else do we have?" Rhyme sipped and puffed and swung closer to the computer. He misjudged and slammed into it, nearly knocking over his monitor.
"Goddamn," he muttered.
"You all right?" Sellitto asked.
"Fine, I'm fine," he snapped. "Anything else? I was asking--anything else?"
Cooper and Sachs brushed the rest of the trace onto a large sheet of clean newsprint. They put on magnifying goggles and went over it. Cooper lifted several flecks with a probe and placed them on a slide.
"Okay," Cooper said. "We've got fibers."
A moment later Rhyme was looking at the tiny strands on his computer screen.
"What do you think, Mel? Paper, right?"
"Yep."