Chapter 4: The Locked Room

By the second day, the blue house smelled of wet ash and old wood.

Mara walked through it with Captain Lyle and a fire marshal named Janice Reed. They wore boots, masks, and the careful silence of people entering a place that had become evidence.

Arthur's downstairs room had survived better than the upstairs. His workbench stood against a wall beneath rows of labeled drawers: fuses, wire caps, brass screws, boat switches. On the other side of the hallway was Erin's room, small and almost bare except for a mattress, a plastic crate, and a gray sweatshirt hanging from a hook.

Blue X-stitches crossed its cuff.

Janice led them upstairs.

The fire had started in the front bedroom. Arthur's blood had soaked into the floorboards near the bed, dark even under the foam residue. The doorframe was split where someone had forced it open after the fire began.

"Look here," Janice said.

At the outside edge of the frame, a bent finishing nail had been hammered through a strip of wood. It had held the door closed from the hallway.

"He was trapped," Mara said.

"For at least a while. Fire pattern says the laundry bag was ignited just outside the room. Not an accident."

"Could Arthur have put the nail there himself?"

Janice looked at her. "Why would he lock himself in and set the hall on fire?"

"Because I don't want a theory. I want exclusions."

Janice nodded once. "Fair enough. No. The hammer marks are from the hallway side."

That afternoon, Simone Hart brought Mara a stack of printed text messages from Arthur's phone account.

"You need the whole relationship," Hart said. "Not the version that makes your case tidy."

The texts were real. Arthur had written: I can help you stay through the heat. We will figure out something long term.

Erin had replied: You promised I would never have to leave again.

Arthur: I promised I would not put you back on the street.

The next message was missing from the printout.

"Why is there a gap?" Mara asked.

"The carrier export has a corrupted section."

"Can I get the phone?"

Hart considered it. "You can get a warrant."

"I already have one."

The recovered phone took a technician six hours to dry and unlock. The missing line appeared below Arthur's promise.

By Friday, Lena will come with us to look at a place. You cannot stay here after that, Erin. It isn't safe for either of us.

Mara read it twice.

Arthur had meant to move Erin, not discard her. Yet he had been frightened enough to call Lena, frightened enough to write a note asking someone to contact him if Erin returned.

That evening, Erin asked to see Mara without Hart.

"She can be present," Mara said. "But she has to know you asked."

Hart entered the interview room five minutes later and sat close to Erin. The fluorescent light turned Erin's skin nearly colorless.

"I didn't start the fire because I wanted him dead," Erin said.

Mara did not move.

"Then why did you start it?"

Erin's lips trembled. "I didn't say I started it."

"You don't have to say anything."

"He was already gone." Erin pressed both hands flat to the table. "He was upstairs. He wasn't moving."

Hart said, "Erin, stop."

But Erin looked at Mara as if the detective were the only person who could translate the terror in the room.

"I didn't start it because I wanted him dead," she repeated. "I started it because I didn't know how to make it not happen."