"Agent Rivers." One of the crime scene techs called from the corner of the chamber. "You need to see this."
Isla picked her way across the concrete, avoiding disturbing any potential evidence. The tech—young, maybe late twenties, with the intense focus of someone who took their work seriously—was crouched near a junction box mounted on the wall.
"Fresh tool marks," the tech said, pointing to scratches around the access panel. "Someone opened this recently. And look—" He shone his flashlight into the exposed wiring. "These connections have been tampered with. This is part of the temperature control system."
Isla felt her pulse quicken. "Can you tell what they did?"
"Not without bringing in a systems specialist, but based on the configuration..." The tech frowned, studying the wiring. "It looks like someone bypassed the safety limits. Basically rigged it so the system could pump way more heat into this section than it's designed to handle."
"How long would that take? To make those modifications?"
"With the right knowledge and tools? Ten, maybe fifteen minutes."
Isla looked back at David Langford's body, at the deliberate burn patterns on his skin. Someone had brought him down here, trapped him in lethal heat, and possibly tortured him before he died. This wasn't an accident. This was murder.
But it wasn't Brune's style. Everything about this was wrong for the Lake Superior Killer—the indoor location, the use of heat instead of water, the deliberate torture element. Brune drowned people and staged it as accidents. This was theatrical, cruel in a different way.
"We're looking at a homicide," Isla said, her voice cutting through the ambient noise of dripping water and humming pipes. Everyone in the chamber turned to look at her. "Someone lured or forced David Langford into these tunnels, modified the heating system to create lethal conditions, and left him here to die. The burn patterns suggest torture, though we don’t know if he was torturing him for information of some kind, or just for the fun of it. Either way,this wasn't an accident, and it wasn't opportunistic. This was planned."
Morrison nodded grimly. "That's what we thought. That's why we called you in."
"I need security footage from every access point for the last forty-eight hours," Isla said, her mind already organizing the investigation. "Personnel records for everyone with authorized tunnel access, particularly anyone with systems knowledge. Background on Langford—work history, personallife, financials, anything that might suggest why someone would target him."
"On it," Morrison said, already pulling out his phone to make calls.
Isla turned to Martinez. "I need everything you can tell me about the tunnel system. Maps, access protocols, who has the knowledge to do what we saw with those temperature controls."
"I'll get you a complete file," Martinez promised. "But Agent Rivers? The list of people with that level of systems knowledge is short. Maybe a dozen people across the whole maintenance department."
A dozen suspects. That was manageable, assuming the killer was actually someone from Public Works. But Isla's instincts were already suggesting something more complicated. The hooded figure on the security footage had moved with purpose, with knowledge of the camera's location. That suggested planning, surveillance, preparation.
This wasn't someone acting on impulse. This was calculated.
"Dr. Henley," Isla said, "how soon can you do the autopsy?"
"I can start this afternoon if you mark it as priority."
"Consider it marked." Isla looked at the crime scene techs. "Process everything. I want photos of those burn patterns from every angle, samples of the modified wiring, any trace evidence you can find. This chamber is a crime scene, and I want it documented thoroughly before we move the body."
The techs nodded, already getting to work. Isla watched them for a moment, then turned back to James, who'd been observing quietly from the chamber entrance.
"What are you thinking?" he asked, his voice low enough that only she could hear.
"I'm thinking this doesn't feel like Brune," Isla said honestly. "The MO is completely different. This is..." She gestured at thescene—the deliberate modifications, the torture elements, the enclosed space. "This is someone else."
"Unless he's adapting. Changing his methods because we're onto him."
Isla had considered that possibility during her analysis last night. Serial killers sometimes altered their patterns when pressure increased, when their usual hunting grounds became too dangerous. But this felt too different, too far outside Brune's psychological profile.
"Brune believes the lake demands sacrifices," she said. "Water is sacred to him. This—" She looked at the steam pipes, at the way heat had been weaponized. "This is fire and metal. It's the opposite of everything he represents."
"So we've got a new killer," James said. "While Brune is still out there somewhere."
The implication sat heavy between them. Two killers operating in Duluth simultaneously—one who'd evaded capture for decades, and now possibly another who'd just announced themselves in the most dramatic way possible. It wasn’t the first time Isla had been chasing two monsters at the same time; she’d been doing it since she moved out here, but now, knowing Robert Brune’s identity, she felt even more pressure.
"Maybe," Isla said, unwilling to commit to that conclusion until she had more evidence. "Or maybe this is exactly what it looks like—a targeted murder of a Public Works employee, with the tunnel system used as a weapon. Not a serial case at all."
But even as she said it, something in her gut disagreed. The deliberation, the staging, the almost ritualistic quality of those burn patterns—this felt like more than a simple murder. This felt like a message.
