She was so angry that she felt tears come into her eyes. "We don't know, but if you'd shared this information with me two days ago, you might have spared another girl from—"

Footsteps echoed in the tunnel. Faith shielded her eyes from the harsh lights and made out a round figure making its way toward them. As the man got closer, she could see that he was wearing shorts, a T-shirt and a white lab coat that was stained with catsup.

"Chuck," Victor said, his voice strained as he tried to get back his composure. He reached toward Faith, but she shrugged him off. He still managed introductions. "This is Faith Mitchell. We were just coming to find you."

By way of greeting, Chuck said, "Shockrete."

Faith asked, "Sorry?"

"Your gray powder is Shockrete. It's a high density concrete that's reinforced with titanium fibers."

"What's it used for?"

"Retaining walls, wine cellars, skateboard parks, swimming pools." He glanced around. "Tunnels."

"Like this one?"

"This baby's old," he said, patting the low ceiling. "Besides, I found granite in the mix."

"Like Stone Mountain?" she asked, referencing a mountain that was several miles outside the city.

"That particular granite is known for its clusters of tourmaline, which aren't common to other granites. I'm no igneous petrologist, but my guess is that it's our trusty three-hundred-million-year-old Atlanta bedrock."

She tried to put him back on point. "So it came from a tunnel in the city?"

"I'd say a construction site."

"What kind?"

"Any kind, really. Shockrete's sprayed on the walls, the ceiling, to hold back soil."

"Would it be used in water main construction, fixing lines under the road?"

"Almost exclusively. As a matter of fact—"

There was more, but Faith was running too fast to hear him.

CHAPTER EIGHTEEN

WILL REPEATED HIS question. "What does the concrete powder look like?"

"Like you'd expect," Petty answered, indicating the glass door Will had just walked through. He could see it now. Light gray footprints across the blue carpet. Will glanced around the room, the furiously working copiers, the empty storefront. Anyone who had been in the Copy Right or the parking lot could have tracked through the concrete dust and deposited it anywhere, but only one of them was holding a knife that matched the one used to kill Kayla Alexander and Adam Humphrey.

He asked Petty, "Are you the only one here?" The man nodded, chewing another bite of steak. "Warren should be back soon. He's out making a delivery." "He has a van?"

"Nah, it's just down the street. We walk over the deliveries sometimes. It kind of breaks the monotony."

Outside, the jackhammer kicked in, the vibrations so hard that Will could feel the floor shaking under his feet.

Will raised his voice, asking, "Do you ever make deliveries?" He shrugged. "Sometimes."

"What?" Will asked, though he had heard the man well enough. "I can't hear you over the jackhammer."

"I said sometimes."

Will shook his head, pretending he still couldn't hear. This wasn't going to be like Evan Bernard. Will would not leave this building without a suspect in handcuffs and a solid case to back the arrest. Petty had the knife, he had the opportunity and he certainly had the motive—what better way to end his illustrious career at the Copy Right than to retire with a million dollars cold hard cash in his pocket? Having Emma Campano in the process would be icing on the cake.

Was that enough, though? Was this pathetic pothead the kind of man who could beat a girl to death and take another away for his own pleasure? Faith had said she'd be the ruler of the world if she could spot a killer from a hundred paces. Was Lionel Petty someone who hid murder in his heart, or was he just caught up in something bad—the wrong place at the wrong time?

Either way, Will wanted to get Petty away from the exit and in an enclosed space where he could talk to him. He especially wanted him to put down the knife.

He told the man, "I still can't hear you."

Petty cupped his hands to his mouth, making a joke of it. "Sometimes I make deliveries!"

Will knew the office was in back of the room. He guessed that all the paperwork would be kept there. He yelled to Petty, "I need to see who you deliver to."

Petty nodded, dropping the knife and standing up. He started to leave, then changed his mind. Will reached around to his paddle holster as Petty's fingers moved toward the knife, but the man only scooped up a handful of French fries. He ate them as he led Will to the back of the store. At the door to the office, he pulled out a ring of keys.

Will asked, "Does Warren always leave those with you?"

"Never, man." He jammed a key into the lock, pushed open the door and sat down in front of the desk. The noise was somewhat buffered in the small room, and Petty spoke in a normal tone. "Warren forgot his keys last night. I don't know what's up with him. He keeps forgetting things." He opened a desk drawer and started to riffle the files. "It's hilarious, because he really hates to fuck up."

Will stood in the doorway, feeling the breeze of the air-conditioning freeze the sweat on his back, gluing his shirt and vest together. He leaned into the door frame, reaching his hand around to his back, finding his gun snugly tucked into the paddle holster.

Petty mumbled to himself as he searched the files. "Sorry, man, Warren has his own system for filing things."

"Take your time," Will said. He looked at the CDs lining the walls, the way the colored jewel cases were stacked together in their own particular order. It reminded him of his own CD collection at home, the way he identified certain albums not by their words, but by their colors, their recording logos, their artwork.

Will felt a prickling sensation work its way up his spine. "What about the customer files on the shelves? Does Warren have a system for those, too?"

"The CDs?" Petty laughed. "Shit, man, I can't even begin to tell you how he's got those filed. I'm not even allowed to touch them."

"But Warren knows where everything is, right?"

"He can find it with his eyes closed."

Will doubted that. Warren would need to see the colors, the patterns, before he could find the disc he needed. "Were you working here the day Emma was abducted?"

"I was off, man. Total headache."

"Is Warren left-handed?"

Petty held up his hand in response. Will couldn't tell which one it was; discerning between left and right was something his brain could not easily manage.

"Here we go," Petty said, pulling out a file. "Ignore the typos. Warren's such a freaktard. He's, like, incapable of spelling anything but he won't admit it."

"What do you mean?" Will asked, though he already knew the answer. Warren color-coded the CDs, relying on visual cues to help him find the right file. The evidence had been staring Will in the face the first time he'd come into the manager's office to look at the security tape. Warren used the color-coding system for the same reason as Will: he could not read.

Petty said, "Warren's all right most of the time, but the dude won't admit he's wrong about anything. It's like working in the fucking White House around here."