They lie sprawled about thirty feet apart. One in the middle of the lane. One in front of his car. Neither of them moving. Blood leaking from their mouths, their ears. It steams in the cool morning air.

He tries to find a pulse on the girl who had been on the windshield. His hand shakes so hard that at first he thinks he feels something. People have appeared, from where he doesn't know. Some adults, some kids from his school. Some run toward the girls, others phone 9-1-1, some stand stock-still, their hands across their mouths, eyes wide.

One guy comes up to him. Bran thinks he recognizes him from his math cla.s.s. "What have you done? You killed them! You killed them!"

He doesn't remember much about the rest of that day. But there was a girl from TIP, and she came and sat with him. She held his hand and gave him tissues and at one point he leaned into her warm neck and wept. Then felt ashamed for weeping, because why was he allowed to cry when these two girls could never cry again?

By the time Bran was finished with his story, Alexis was crying, too, but he was dry-eyed.

"There were a lot of rumors going around. They still go around, in fact. That I was drunk. That I was texting. That I knew one of the girls and meant to hit her. They call me a killer behind my back. Sometimes to my face. It doesn't matter the police investigated and ruled it an accident." He makes a sound like a laugh. "Sometimes it doesn't even matter to me. Because I can think of a million things I could have done so that it didn't happen. So that's why I volunteer for TIP. And that's why I've been acting strange. Because what happened Sunday night, that guy in the pickup hitting the little girl, brought it all back."

Instead of saying something, Alexis pulled him close.

CHAPTER 28.

PAUL.

THURSDAY.

DNA DOESN'T LIE.

"This can't be right," Paul said, looking up from the crime lab's printout that Rich had just triumphantly slapped in front of him. "I know this kid."

Rich was practically dancing in Paul's cubicle. "DNA doesn't lie, my friend. You trying to tell me that it's just a coincidence? Someone you already know was in the area at the same time the victim was killed, and now his DNA profile turns up under her nails?"

"But it's not his full profile."

Rich stopped his jitterbugging long enough to shrug. "We can get a court order and get that taken care of pretty quick."

Paul waited until Rich left to call the lab. "Can you just walk me through this? I'm still kind of confused by the results."

"I can do that," said Gunther Schmidt, the DNA specialist. He had a precise way of speaking, perhaps because he was a scientist, or maybe because his native tongue was German. "The only DNA we found on the brick belonged to the victim. Same for her clothing items. We did find male DNA on the clippings and swabs from her right hand."

Paul pictured it. The same hand that had lost the glove. She must have fought with her killer.

"The quant.i.ty of male DNA was very small. It was masked by the female DNA on her hands."

Paul nodded, even though the other man couldn't see him. That all made sense. It was Lucy's hand, after all.

"To allow us to focus on just the male DNA," Gunther continued, "we ran a newer test. It's called Y-STR typing. Remember, only males have the Y chromosome."

"Uh-huh." Paul closed his eyes to help him concentrate. When it came to DNA, it was all too easy to get lost in the weeds.

"The Y-STR test looks at certain locations on the Y chromosome that are pa.s.sed down undiluted from each man's father. Since it never mixes with the mother's DNA, it never changes except in the rare case of a random mutation. That means all the males in a family have exactly the same Y-STR profile: fathers, grandfathers, sons, uncles, brothers, and so forth."

"So my brother and my dad and me-there's a part of our DNA that's identical?" The idea was slightly creepy. Didn't you want to be different from your family, to make your own path?

"Exactly so." Gunther made a small chuckle at his own pun. "And under Oregon state law, we are now allowed to do a familial search if there is no perfect full DNA match in the system. So we found a match for the Y-STR from the victim's hand."

"So that means the person whose Y-STR matches did it?"

Gunther didn't bother to disguise his sigh. "Obviously not, given who it matches. But he is probably a relative. If he somehow had been able to do it, the DNA would have been a perfect match. The entire sequence is as unique as a fingerprint. One in 244 males has this particular Y-STR."

"So it's a relative?" Whether it was nature or nurture, Paul didn't know, but about half the people serving time had had at least one close relative who has also served time.

"At some point even two unrelated men who have the same Y-STR probably still share a common male ancestor. Until I have a complete DNA profile that I can match to what was found on the victim, I can only give you the numbers and the probabilities as to whether your suspect might have done it. You have to look at the totality of circ.u.mstances."

Paul thanked Gunther and hung up. Right now, this particular Y-STR test was a noose that was closing. Only Paul couldn't believe the ident.i.ty of the person caught in it. Twenty years a cop, and he could still be surprised. He sighed. And he had liked this kid.

CHAPTER 29.

NICK.

FRIDAY.

IF YOU WERE THE KILLER.

When the phone on the wall rang, Nick's English cla.s.s was taking a pop quiz.

"Must it be right now?" Mr. Dill said after listening to whoever was on the other end. "He's taking a test." Everyone was watching the teacher, praying that he or she would be the one. But it was Nick who won the lottery. "You're wanted down in the office," Mr. Dill said, adding when he started to leave, "You might want to bring your things."

It was even more of a surprise to find Detective Harriman waiting for him. He was dressed in a rumpled black suit and an even more rumpled trench coat. Nick hadn't seen him since the evidence search four days ago.

"Hey, man. What are you doing here?"

The office lady, Mrs. Weissig, looked from Harriman to Nick and back again. She was making no pretense of not listening.

Harriman pulled him to one side and lowered his voice. "I got to thinking about what you told me Monday. I talked to the pathologist. The time you were driving down the street was the time he believes that girl was killed. It would be good for you to come down to the police station and complete a witness statement for me."

"But I'm not a witness," Nick said, wishing he were. "I didn't see anything."

Harriman shrugged. "You could have seen something without even being aware of it, or at least aware of its significance."

What if he had seen a key piece of evidence? Nick imagined the headlines. Maybe he'd even get some kind of award.

"And sometimes not seeing something can be nearly as good as seeing something, because it can help us rule out certain scenarios. We need what you saw-or didn't see-on the record. I already talked to your mom so she wouldn't worry if you were home late."

Nick signed himself out, writing "consulting with police" under Reason for Absence. If only there were someone else in the office besides Mrs. Weissig to notice him leaving with a homicide detective.

As they drove downtown, Harriman said, "So this happened in your neighborhood, Nick. If you were the killer, where would you hide the knife?"

Six or seven blocks away from his house wasn't exactly his neighborhood. Nick didn't know every bush and culvert the way he would on his own block. Still, Harriman was waiting for his answer. "Maybe try storm grates? Or people's bushes?"

Harriman nodded, but they were pretty obvious answers. When Harriman was busy circ.u.mnavigating a slow-moving truck, Nick quickly texted Alexis and Ruby with one hand to let them know about the latest development. When they got downtown, Harriman parked in one of the s.p.a.ces reserved for the police, and then they walked into headquarters together. Nick held himself tall as a few officers nodded at them.

Once on Harriman's floor, the detective led him back past a warren of cubicles to a blank, impersonal room. Nick had been here once before, to pick out the photo of a person the police thought was a killer. The room held a table and two chairs, one on wheels and one without. Harriman took the one with wheels. Nick sat down on the other and put his backpack on the floor between his feet.

Two brown cardboard boxes, about the size of small pizza boxes, lay on the far corner of the otherwise empty table. Each was printed with the word Evidence in big black letters. The preprinted lines had been filled with scribbled notes Nick couldn't make out.

"Are you chewing gum?" Harriman pointed at the wastebasket. "Because you can't in here."

"I'm not." Gum made Nick think of Ruby and her obsession with unusual gum flavors.

"Before we start, Nick, are you hungry? Thirsty?"

"I'm good." It was weird to have Harriman being so solicitous, but it must be because Nick was key to breaking this thing open.

Harriman looked at the phone in Nick's hand. "Would you mind turning that off while we're talking?"

"Sure." Nick set it to vibrate and slipped it into his pocket.

"So if you were this guy, how would you have killed her?"

Nick grimaced. "I don't know."

"Come on. Help me out. I've been thinking about it so much I can't even think straight. How do you think you would do it?"

It was kind of flattering that the detective was looking to him for help. Nick tried to think. "I guess I would go in low." He held out his hand, curled around an imaginary knife, and demonstrated. "Into her belly. And then up. So you could get past the rib cage."

"Remember, Nick, you're holding a knife. So why is she going to be standing facing you? No, she's going to be running away, isn't she?"

Nick was letting the detective down. "I don't know. Then in the back, I guess."

Harriman reached over, picked up the top evidence box and opened it. Inside was a clear plastic envelope, and inside that was a knife.

He slid the box toward Nick. "What could you tell me about a knife like this?"

CHAPTER 30.

NICK.

FRIDAY.

GOOD FOR STABBING.

Nick's pulse sped up. He reached out a hand, pulled it back. "Oh, dude. Did you find that at the crime scene?" He didn't see any blood on the blade, but the killer could have plunged it into the earth or wiped it clean on his pants.

Harriman tilted his head and just looked at him from under his s.h.a.ggy eyebrows. Nick realized he probably wasn't allowed to ask.

He leaned over it. "I've got a knife a lot like this. A lot." It looked like the combat knife Jon had told him not to carry.

"You do?"

"You know. For SAR. There's a million things you need a knife for out in the field. You might need to cut someone's clothes to get at an injury, or saw a branch to make a travois, or cut a rope or something."

"Do you think this knife would be good for stabbing? Like, do you think someone could have used a knife like this to kill that girl?"

Nick regarded it. "Maybe. But I think that jagged edge on the back of the knife-the saw back-would make it hard to pull it out." In history, they had just seen the movie All Quiet on the Western Front, which he thought might have been based on a book. In the movie, an officer had lectured a recruit carving notches into a knife blade, telling him it would make it harder to pull back out of the enemy.

Harriman was silent. Nick wondered if the movie had been wrong. He decided not to bring up the knife in his pocket. He didn't want to get in trouble for bringing it to school.

Finally, Harriman said, "Why do you think this girl was killed?"

Nick tried to think of why. "Did they steal anything from her?"

"Not that we know of."

"Did they rape her?"

"No. So why do you think they did it?"

"I don't know. They'd have to be sick." He imagined how awful it had been for that girl. Lucy. Running in the dark. Being stabbed. Being hit in the head. Being dragged. Being discarded like a piece of trash. Being left all alone as your life ebbed away.

"I wonder what you would say if I told you something, Nick." Harriman was looking straight at him.

"Told me what?"

"That knife doesn't just look like your knife." He paused. "It is your knife."

"Wait. Why do you have my knife?" Understanding dawned. "Do you think I'm the killer?" Nick tried to laugh, but it came out sounding broken. This couldn't be happening to him. "I don't even know that girl. I was never anywhere near her."

"But you were, weren't you, Nick? You told me yourself that you drove down that street at the time she was attacked. And yet you claimed you didn't see her."

Harriman was suddenly acting like they were on opposite sides. But how was that possible? Nick was in SAR. He was going to join the army. He was one of the good guys. And Harriman knew that. His scalp p.r.i.c.kled. "Because I didn't. How can you even think that? Why would I have told you that if I killed her?" His mouth was suddenly dry, and he forced himself to swallow.

Harriman seemed unconcerned. "Because you knew it would turn up. You knew we would look at footage from nearby security cams, probably see that you had been there. That forced you to tell the truth."

"So if I'm honest, if I tell you the truth, then that's just more proof that I'm lying?" He could feel his pulse in his temples and at the base of his throat, as if he had just run a mile. His phone buzzed in his pocket, but he ignored it.

Harriman kept on as if Nick hadn't spoken. "You drove down the street and what-you saw her walking? We know she'd been drinking and she was upset. Did you offer her a ride? Because it was cold? Because you saw her crying? Because you were worried about a girl walking alone at night?" He sighed. "And then something went wrong."