Then Jess walked back inside the storage unit through the waterfall of rain.

“Let’s go,” she said to him. “I’ve got a forensics team on the way, and the boy outside will keep this place secure until they get here.”

“Go where?” Frost said.

“The Night Bird just turned his phone back on,” Jess told him. “We got a ping.”

The GPS signal took them to one of the neighborhood’s ruined industrial sites. It was a three-story building, stretching the length of a football field. The walls were red brick, mottled by decades of salt water carried off the bay. Round arched windows lined the wall facing the street. The ground-floor glass had been replaced by heavy plywood, and above it, the windows were pockmarked with cracks and bullet holes. A barbed wire fence surrounded the entire property.

They parked a block away. Lightning lit up the night sky in streaks above the angled roof. Frost could feel the thunder under the street. He left Frankie behind in the Suburban, and he joined Jess and half a dozen other officers as they converged on the shell of the building.

“He knows we’re coming,” Jess reminded them.

Their flashlight beams led the way through the rain. They followed the fence along the exterior of the building, and when they reached the back corner, they found a section of netting that had been cut away, opening up a way inside. One by one, they pushed through the gap in the wire. The building wall was in front of them, and the plywood blocking the first window had been splintered with an ax, which lay on the sidewalk.

“Welcome to the party,” Frost murmured.

Jess went inside first. Frost followed.

The stone floor was a minefield of debris. His light passed over rusted tools, jagged chunks of mortar fallen from the ceiling, and garbage left behind by squatters who’d broken in over the years. Concrete support columns with peeling white paint made a row of soldiers from one end of the building to the other. The wind whistled like a ghost through broken windows. Standing pools of black water reflected the glow of the flashlight. He smelled mold and dampness in the shut-up space. It was cold.

Jess sent two officers along each of the perpendicular walls. She and Frost picked their way through rubble toward the center of the building. Each step dislodged rats, who squeaked and scurried. Rain squeezed through the ceiling. Drip. Drip. Drip. They didn’t hear anyone else inside the ruins.

Ahead of them, open stone steps led toward the building’s second floor.

“There’s a light up there,” Jess murmured.