Page 53 of Slack Tide Kill

The words washed over Sally. She wasn't entirely sure what she'd just heard, and certainly wasn't sure what it meant. But eyes? "That's it," she muttered.

"I think so, yes."

"What does it mean?" Liam demanded.

Collier shifted toward Liam. "The true meaning has been debated for two and a half thousand years, Officer O'Connell. Socrates himself struggled with Heraclitus. His peers called him the 'weeping' philosopher for his misanthropic worldview. But consensus suggests the B107 fragment means that those without wisdom are doomed to misunderstand the fundamental truth of the sensory world. For him, that truth was the primacy of chaos within order, or order within chaos, where chaos itself is the only true law."

Sally exhaled. "Order within chaos? What even is that? And how does it apply here?"

Collier looked to the side and Knight took over.

"We believe with the first killing three decades ago, your killer posed a question. One about chaos and order. They then waited 30 years to kill again, with a repeat of the same murder that now answers that question."

"So the murder's an answer? What's the question?"

"We don't know. But we can infer a great deal from the 30-year dormancy; a period of self-control most serial killers never manage. BTK paused 15 years. The Grim Sleeper roughly the same. Dahmer nine. None approached 30. It is an extraordinary length of time to resist such a powerful compulsion."

Sally instinctively began looking for gaps. "Maybe our killer was incarcerated. Maybe they committed murders that were never found."

"We are weighting against that," Knight intoned. "Searches of lengthy local prison sentences show little relevance. As for hidden murders, this is clearly a mission-oriented killer. They have a message. Killing in secret would not serve their compulsion."

"So, uh…" Sally tried to straighten that out. "So they stopped killing for 30 years, contemplating this question. How can we use that?"

"It informs what the killer likely did within that dormant period. We believe they channeled their 'mission', seeking to answer their own question through a lifetime of experience. This could be chaos-based, involved deeply with the shifting landscape of Dungeness: the beach, the sea, the marshes. They may have worked in local museums or archives, sat on drainage boards, been involved in coastal defense, ecology or history."

Sally's eyes darted to the whiteboard, with its list of the Rook men. She couldn't picture any of them in a museum or sitting on a board. But Reactor Logistics was involved with shifting the shingle on the beach…

"What about order-based?"

"It is possible the killer worked in the judicial system, within the police, as a firefighter, a member of the RNLI or the Coastguard, or even within health care. Any one of these professions would allow the killer to refine their answer over the decades, always with life and death stakes."

Sally released a long breath. That second list seemed to encompass everyone she'd met on Dungeness so far. Every police officer. Every paramedic. Every worker in the reactors. All dealt with life and death, all involved the beach or the marsh.

"We need to narrow that down."

"Quite. Your investigation requires concrete detail, and there we can offer assistance. Firstly, IQ. We do not believe the killer has an outstanding intellect. The thinking is too muddied, the historical references a hodgepodge. There is no clarity."

"But they were never caught."

"I did not say they were incapable. They are clearly patient. Practical. Locally expert, capable of blending in for three decades. Those are dangerous qualities."

"You think they've been hiding here all this time? In plain sight?"

"Yes. We do."

Sally exhaled. "Anything else?"

"Age and gender can be inferred. The average age of male serial killers upon their first kill is 27.5. The youngest begin at 19, but they are outliers. Given this, your killer is likely in their late 50s now."

Sally's eyes snagged on Reg Rook at the center of her whiteboard. "What about generational killers? A mission handed down from father to son?"

"Less likely. They would have to share the same defining pathology, the same all-consuming mission, and that is rare."

"Then multiple killers? We have a witness saying that two or three boats brought the body to the beach."

"Also unlikely," Collier answered. "Outside of fiction, such group killings are rare, and generally limited to male-female pairings, such as Fred and Rose West, the Moors Murderers, the Ken and Barbie killers. But those killings were hedonistic. Mission killers are invariably solitary."

"That doesn't help. Our witness saw what he saw. Two or three boats. That means at minimum two or three killers, or accomplices, or something."