Page 44 of Absent Reason

His first instinct when the FBI agent walked away from the bridge was to go after Nicole, to try to get to her before anyone could arrive to help her.

Swiftly, though, flashing lights appeared near the bridge, and two cop cars pulled up next to it. Cops got out, beckoning Nicole over to them. There was no chance of getting to her now, not without being caught. It wasn't as if he'd brought a weapon other than the rope he used. He'd never needed one, and he'd always calculated that if the cops ever got too close to him, he could abandon the rope and just walk away. They would never be able to link anything to him.

His next instinct was to do exactly that, to just walk away into the night and disappear. It was obvious that the cops didn't know who he was, not yet, or they would already have come to his home and arrested him.

The FBI agent's words stopped him from doing that. She claimed that she was some great puzzler, that she'd already solved the problem that he'd set and that Professor Arran had taken the credit for.

That was what came of being stuck as a TA. He had a doctorate, he was as intelligent as anyone at the university, but there was no tenure, no respect. He was there to teach classes and mark work, little more than a functionary.

He'd definitely not gotten respect from the women he'd killed. They'd ignored him or laughed at him. They hadn't taken his work seriously. The problem he'd created had been meant to be his ticket to more. The moment when Victoria Crossing solved it tore his world apart.

So he'd decided that she would pay. She, and the others who had denied him, belittled him, and pretended that they were so clever. As if any woman could ever be his intellectual equal.

He tore his thoughts away from the others. He had to focus on Amber Young. He would get the chance to kill her before the night was done.

She thought that she was superior to him. She thought that she could solve any problem that he could set, but she was so stupid that she was trying to solve an impossible problem. He would follow her; he would wait for the moment when she realized that she'd overestimated her own capabilities when she realized that she couldn't solve this puzzle.

That was when he would hang her from the edge of a bridge, the way he had with the others.

He watched as she walked across the first bridge, her movements deliberate and calculated. The game had begun.

He followed her, staying hidden in the shadows. He had to be careful not to give himself away. He guessed that was at least part of her intent: to try to get him to show himself so that the police could take him down.

Yet he couldn't see any police nearby. She'd miscalculated. They weren't coming to save her.

As Amber Young quickened her pace, he did the same. Yet he didn't follow directly behind her now. He didn't need to. One of the beauties of the bridge problem was that he always knew where the women he stalked would be heading next. He hurried on down a side street, determined to get ahead of Amber Young.

She was arrogant enough to think that she could solve an impossible problem. Well, she would pay for her arrogance soon enough.

CHAPTER TWENTY SEVEN

Amber held her breath as she started to cross the sixth bridge. With every bridge she crossed, the odds of the killer trying to attack her went up. With everyone, there was a chance that he would decide that she had taken a route that made it impossible for her to finish the puzzle.

Now, on the sixth bridge, the odds of that were at their greatest. This was the point where Amber had no options left, where she couldn't choose between different bridges to cross anymore. She was committed now. There was this bridge and then the seventh.

The problem, of course, was that it was impossible to walk to the seventh without crossing back over the bridge.

"I know that this is the Konigsberg bridge problem," Amber said as she walked. She had to assume that the killer was close by now. "I know that Euler proved it to be mathematically impossible."

She said it to buy herself time. She wanted the killer to wonder why Amber had done this at all if she knew that it was an impossible problem. Amber had to fight to keep her hand from her gun tucked away beneath her suit jacket. She didn't want to scare the killer off; she wanted to draw him in.

Amber kept walking over the bridge, looking around with every step, unable to keep herself from looking for any sign of him. This bridge was large and steel-built, with girders rising high over Amber's head. Briefly, Amber shuddered, imagining a rope dropping down on her from the darkness above, wrapping around her throat before she had a chance to stop it.

She had to force herself to keep walking, to keep focused on the task at hand. She knew that she had to get to the end of the last bridge before the clock struck midnight, or she would fail the puzzle. She couldn't let that happen.

As she reached the other end of the bridge, she let out a sigh of relief. She had made it. There was only one bridge left to cross, and then she would have completed the challenge. She looked around, trying to spot any sign of the killer, but there was nothing.

"Where are you?" she muttered under her breath. "Come out and face me."

She knew that it was a foolish thing to do, but she couldn't help herself. She was tired of being hunted, tired of being afraid. She wanted this to be over, one way or another.

Amber looked down towards the water. It was time to hope that Chief Williams had done what Amber had asked of him.

She breathed a sigh of relief as she saw a small rowboat tied up there on the bank near the bridge, exactly where Amber had asked for it to be left.

In the original problem, it wouldn't have counted. The Konigsberg bridge problem was a logic puzzle, and it relied on those trying to solve it doing so according to the implicit rules of the scenario. The goal was to walk over all seven bridges, and it was implied that one should travel between them only by walking. In the original problem, swimming or taking a boat would represent a failure.

"You know that you don't set the parameters for your problems tightly enough, right?" Amber called out to the night. "That was what went wrong with the one Victoria Crossing solved. You assumed that people had to solve it the way that you wanted."

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