Joanna parked and approached the West Block, glancing at the entrance to the North Block only briefly. She knew that Gregor’s flat had been sealed by the CSI team, who would be back the next day to complete the work. They’d taken samples, fingerprints, and photographs. Tomorrow, the search would get a bit more structural: one of the officers had noticed an area of plaster that was newly replaced, and had sought permission to open up the wall. For now, though, the entrance to the block looked as it always had. There was no police tape, no officers guarding the building, no sign that anything untoward had happened there. Apart from one small thing. Someone walking by wouldn’t notice, but Harper knew that if you looked carefully, there were still drops of Gregor’s blood on the paving. She refused to imagine Ruby wielding the weapon that caused those injuries; the figure she pictured carrying out the crime was faceless, with a rope of jet-black hair. Whatever she imagined, she knew it was probable that Ruby had been in Gregor’s flat very recently, and it was only a matter of waiting for CSI to analyze the DNA and fingerprints. If—or more likely when—they connected those samples to Ruby, it was a short step from Ruby to Jo. Joanna would find herself answering one or two awkward questions about withheld information and bias. She had to make the most of what little time she had.

At the entrance to the flats, she pressed buzzers randomly until she got a response.

“Yes?”

“It’s the police. I need access to this block.”

Whoever it was simply hung up on her, so she tried again, and the second person who answered was more amenable. She heard the buzz as the electric lock disengaged. She pushed open the door to the stairwell.

On the seventh floor she found Ruby’s door and knocked loudly, announcing her name and rank, mostly for the benefit of the neighbors. She wasn’t expecting an answer, and so there was barely a hesitation before she swung the bag containing the Enforcer off her shoulder onto the floor and unzipped it. She took out the heavy metal cylinder, positioned it, took aim at the lock.

“Step away from the door. I’m going to force the lock, in five, four, three, two—”

“What are you doing?”

She froze, looked to her left. It was Atkinson. Surprise turned quickly to anger.

“What am I doing? What are you doing? You’re supposed to be searching the beach at Cleethorpes.”

“I ended up behind you in traffic. Then I saw you were coming in here and I thought maybe you’d need help.”

“You followed me.”