Zoe saw formations of weeds indicating the spread of seed in the wind, and she noted a worn-down path indicative of lazy feet shortcutting through the grass on their way to the road. She saw a deflated ball that told stories of local children playing in the area, but there was no dug-up and replaced soil. No dropped trinkets or items of clothing. No spatter of red blood standing stark against the green blades of grass in the beam of the torch’s light.
At last, they were done, and still none the wiser.
Zoe and Shelley waited in the middle of the road as the search team from the other side of the street joined them with shaking heads and rounded shoulders, and they moved up to the other houses.
“They are outside of the range,” Zoe said, chewing her lip.
“I know, but it’s better to check,” Shelley told her. “He was under stress. Maybe he made a mistake.”
And so they woke the startled homeowners, and made them stand shivering in their pajamas on the cold lawn while they searched through every room for any sign of something abnormal. There was nothing in the attic. The house didn’t even have a basement. No doors or windows had been forced, and no one had any relation whatsoever to the man they now knew was their killer.
There was no sign of her.
And when the other teams finished their searches without bringing up a single sign of Aisha Sparks either, Zoe knew that something was wrong.
“This does not make any sense,” she said, slumping into the passenger seat again to rest. No matter how she thought about it, they had to have made the right calculations. The logarithm was not affected by human error. It had been correct about the last location. And they knew already that the man would never have deviated from the pattern, from the precise calculations they had used. He could not. It was not within his range of abilities to do so.
Beside her, Shelley climbed back behind the wheel, shifting on the seat to face her. “We have to think about it, Z,” she said. “We’re missing something. She isn’t here yet.”
“What was that? Say that again.”
“She isn’t here yet?”
Zoe nodded furiously, her mind whirring. “She does not have to be here yet. Not now.” She checked the dashboard clock. “We still have six hours until dawn. She is not here now. But she will be tomorrow.”
“How is that possible? The killer is dead. He can’t bring anyone anywhere.”
“Then there has to be some kind of outside force that we have not yet considered.”
Shelley sunk her head into her hands in a momentary fit of despair, before raising bloodshot eyes again. “You sure the numbers are right?”
Zoe nodded once. “I have checked everything. We inputted the correct data, and the map stands up. A perfect Fibonacci spiral. There is nowhere else he could possibly go.”
“All right.” Shelley thought for a few minutes more, both of them aware of the unrelenting and callous tick on of the clock. “Maybe he has an accomplice. Someone who helped him get this far.”
Zoe thought back. “But there was no evidence of another person at the crime scenes.”
“There was barely any evidence of him at the crime scenes,” Shelley pointed out. “What if this person stayed in the car every time? If their feet never touched the ground then they couldn’t leave footprints. Maybe it’s a woman, someone who would help him lure in his victims.”
“He came in alone at the diner. A time when he needed a cover more than ever.”
“Because she was already with the teenage girl, taking her away. Hiding her. Getting ready for tomorrow.”
Zoe cocked her head. She had to admit, it held some water. “It would be peculiar for someone to maintain the same level of delusion. The apophenia. I have to admit, it would surprise me.”
“Me, too,” Shelley replied. “I don’t like the idea of something coming out of left field at the last minute, something that we never saw coming, never had any clues about. But it’s a possibility.”
Zoe’s mind was already moving forward, running toward other options. The idea of other people being involved opened doors. “Her family may be involved somehow,” she said.
“Her family?”
“Maybe he threatens them. Forces them to report her missing so that we will be looking in all of the wrong places.”
“I’m sure the troopers knew to check her house first,” Shelley protested.
“Maybe not, if they already knew we were dealing with a serial killer.” Zoe paused, chewing a fingernail. “He tells them they have to send Aisha out here at a certain time. They do not know that he is dead. They follow through.”
“What threat could he possibly offer that would be a worse prospect than sending their daughter out alone and vulnerable?”
Zoe shrugged. She had no answer for that.
“It’s a thought, anyway.” Shelley opened the door again and swung out of the car, leaning back in to talk. “You sit here and rest. You shouldn’t be running around like this. I’ll talk to the troopers that interviewed her parents, and organize another search party for her house.”
It was something. Then again, it could be nothing. Zoe sat back, closing her eyes against the patterns of lights and the low voices outside, trying to block everything out but the pattern. She had to concentrate. There had to be something else, an answer to this. Six hours, maybe less. Aisha waiting for rescue, maybe scared, maybe alone. The last person they could possibly save. If they didn’t get this one, they would have lost them all.
Then Zoe thought about the expanse of grass beside the houses. The reason they had had to search empty ground, and not more buildings. This was the middle of a town; the developers would have built more housing there, unless they had a very specific reason not to.
And they had a reason not to. The train track that ran through the lower edge of the grass on the west side, the side that Zoe and Shelley had not personally searched. It ran at an angle to the road, cutting on through the land with the quickest possible route toward the nearest major town.
Tracks held trains, and trains held people. Trains moved people and things on a set schedule.
It was possible, in fact, to know when the first train would pass through any given area for the first time in a new day.
And she knew that she had him.
Zoe scrambled out of the car, nearly tripping over her seatbelt as it tangled in the ache of her arm and dangled below the edge of her seat. She jogged after Shelley, catching up with her as she left off talking to a cluster of troopers, all of whom were now turned away and talking on cells and radios.
“Train schedule,” she said, the cold air biting off her words in a white cloud.
Shelley gave her a baffled look. “What?”
Zoe bit back exasperation. It wasn’t Shelley’s fault that she had not been inside Zoe’s head, listening as she worked it all out. “I need the train schedule for those tracks. We need to know when the next trains will be coming through.”
Zoe saw the moment that understanding flashed through Shelley’s eyes, even in the gloom and contrast provided by the flashlights around them in the darkness. Shelley fumbled for her phone and searched up local contacts before making a call, stalking away from the group so that she could hear herself talk.
Zoe watched her grab a notebook from her pocket and lean it on the hood of their car, using the illumination from the interior light as she jotted down a series of notes. One, two, three, four—seven lines on the paper. Zoe crept closer, watching with bated breath until Shelley hung up the call and lifted the pad in the air.
“The first train passes through before dawn,” Shelley said. “Four a.m., a freight train. They continue at half-hour intervals, until the single passenger train at a few minutes past seven a.m. I’ve ordered them to stop all trains leaving the rail yard and passenger depot, but we still need to find her.”