In the hours before dawn, the streets belonged to her.

Not to the hurried commuters, umbrellas angled against the rain, not the tourists with their expensive cameras and vacant smiles, not the workmen in their yellow hardhats, beefy hands wrapped around Styrofoam cups.

To her.

Shrap sat on the low concrete wall separating St Thomas’s Hospital gardens from the South Bank and watched as the sun painted the Houses of Parliament a burnished gold. The river walk was empty. She glanced along it, then down the other way. There was nobody in sight.

The river rushed past, governed by man-made tides, unable to do what it wanted. The surface was still, but just beneath she could see flurries and eddies, a sure sign the undertow was strong and relentless.

A port authority patrol vessel appeared from around the bend, kicking up white water as it raced by. Two men hunched over the bulkhead in high-visibility jackets. Shrap wondered if they were going on a rescue mission. A hapless kayaker, perhaps?

Then it was quiet again.

The frosty chill in the air whispered winter was coming. She pulled her long coat around her and rubbed her hands. It would soon be her second winter on the street. Practically a lifetime.

She spun around at the crunch of boots on the gravel path behind her. Two police officers, a man and a woman, were approaching. Without thinking, Shrap slipped her hand into her leg pocket and withdrew her knife, then put her hand behind her back, over the wall.

She scowled as they smiled. Forced smiles, non-threatening, designed to reassure. She used to have a smile like that.

“Are you Shrap?” enquired the female copper, looking her up and down. She was in her mid-twenties. Pressed trousers, white shirt, shiny shoes. They both wore stab vests.

Shrap nodded warily.

“I’m Sergeant Baxter and this is Sergeant Willis. We’d like to ask you a few questions.”

Willis stood further away from her than Baxter like he was afraid he’d catch something if he got too close. He had a pasty complexion, pale, judgmental eyes, and a bland expression that she found annoying.

“What about?”

“Do you know this man?” Baxter held up a grainy photograph taken from a CCTV camera of a white-haired man in his sixties, slightly stooped and lopsided, head down and to the side so that only part of his face was visible. He appeared to be in a hurry, his mouth pulled downwards in a misshapen O.

She nodded again. “What’s he done?”

“What makes you think he’s done something?”

Shrap gave them a hard look. “Why else would you be here?”

The woman paused.

“As it happens, we are trying to locate this man. Do you know where he is?”

Shrap frowned. “No, he moves around.”

“When last did you see him?” asked the male officer.

Shrap shrugged. “Couple of days ago.”

Baxter cleared her throat. “Would you mind accompanying us down to the station, ma’am?”

Ma’am. She hadn’t been called that in a long time. “What for?”

“To answer some more questions about your friend.”

“Who said he was my friend?”

“You seemed concerned about him.” She flushed and glanced at the ground. “Apologies if I misunderstood.”

She wasn’t wrong. Doug was a friend. Shrap decided to stop giving her a hard time.

“I know him, that’s all.”

Baxter gave a little nod.

“Will you come with us?” asked the pasty-faced officer.

She dropped the knife into a flower bed to be retrieved later. The sunrise was ruined anyway. The moment was lost. She loved that short interval after daybreak when the world was doused in a rosy glow and anything seemed possible, before the glare became too bright and the cracks began to show.

“Yeah, I’ll come.”

She swung her long legs around and jumped off the wall.

“You carrying any weapons?” Pasty Face asked.

“No.”

He glanced at his colleague, who flushed. “Mind if I pat you down?”

Rookie, still getting to grips with the job.

Shrap raised her arms. “Go ahead.” Standard procedure. She got it. They didn’t want any nasty surprises.

Baxter searched her for weapons, and finding none, gave a stiff nod. “Thank you, ma’am. If you’ll come with us.”

Southwark Police Station was a ten-minute drive away. As she sat in the back of the patrol vehicle, Shrap tried to make sense of the situation.

What the hell had Doug done? Why were the police looking for him? The guy was a harmless old drunk. A vagrant nobody cared about. Unless you counted loitering, Doug hadn’t committed a crime since he’d gone AWOL from the armed services twenty years ago.

The police car drew up outside and Baxter, who’d been sitting next to her, got out. “Follow me.”

Pasty face, who was driving, didn’t turn around.

Shrap got out and stared up at the mismatched building with its dark- and light-coloured bricks and concrete base. The cobalt-blue plaque above the door read Metropolitan Police. Attached to the wall above the entrance was an old-fashioned Victorian streetlamp, the glass the same reassuring blue.

Baxter pressed a buzzer and the door clicked open. Shrap had never been inside this building before, but all police stations looked the same. Bare lobby, harsh lighting, sombre-faced duty sergeants behind a smudged plexiglass screen desperate to knock off.

Baxter greeted the officer behind the desk and gestured for Shrap to follow her. They went through a revolving door and down a cold, unwelcoming corridor. At the other end was a large office, bustling with activity. Three police constables manned a long reception desk, computers hummed, and printers spat out charge and release forms. Somewhere, a radio crackled.

“D5 would like a drink of water,” barked an overworked custody officer, appearing from a side door. “And DI Bailey is waiting for C2 in Interview Room 3.”

A detainee shouted something obscene from inside one of the holding cells. The custody officer rolled her eyes. “He’s still pissed.”

“Hi, Gloria. Who’s this?” The constable behind the desk gazed at her.

Baxter put a hand on Shrap’s shoulder. “This woman has come in voluntarily. Detective Constable Trevelyan wants to interview her.”

“Name?”

“Shrap,” said Shrap.

“Surname?”

“Just Shrap.” The constable arched a tired brow but wrote her name down, then checked the digital clock behind her and added the time. “Put her in Interview Room 2. They’re finished in there now.”

Baxter led her down a short flight of steps and along another passage. Everything was painted in a suffocating aquamarine. Shrap felt like she was swimming underwater.

“If you’ll wait in here.” Baxter opened a side door and gave her an awkward smile.

She went inside.

The smell of sweat and fear from the last inhabitant was so vivid, Shrap gripped the rim of the chair and closed her eyes. Déjà vu sucker-punched her in the gut.

She was on the other side of the table.

She was the one in charge, calling the shots. The interrogator, calmly and relentlessly breaking down her suspect. Finding cracks in their story, then prising them wide open.

But that was another life. Another person. Someone she couldn’t relate to anymore. With a sigh, she sank down into the chair. It was bolted to the floor.

She didn’t have to wait long.

“Thanks for coming in.” A lanky man with an earnest face, curious eyes and unruly brown hair that he’d tried unsuccessfully to tame strode into the room. “I’m DC Trevelyan.”

Shrap got up and held out her hand. He seemed surprised but shook it without hesitation.

“Please, sit.”

She did so, keeping her eyes on him.

He wore a classy suit, middle of the range, probably from somewhere like Marks and Spencer, in a gun-metal grey. Not too cheap, but not hugely expensive either. A crisp white shirt and black tie completed the outfit. Sensible, smart, appropriate. He placed a manilla folder on the table, sat down and studied her.

“Is Shrap your real name?”

She stared back at him. “No.”

When she didn’t say anything else, he gave a curt nod, opened the folder and slid the same photograph the policewoman had shown her across the table. “I won’t take up much of your time. I just have some questions about this man.”

She studied it under the fluorescent light, looking for clues. No street names, no recognisable features. Doug stood beside a high brick wall; some cabling was visible overhead. Train lines? On the opposite side of the road stood a hulking grey building with dark basement windows. She couldn’t remember seeing it anywhere.

Doug was a creature of habit, though. He wouldn’t venture too far from his usual haunts.

“I believe you know him?”

“Yes, I do.”

“Who do you know him as?”

So, they didn’t have his name either. She wasn’t sure she wanted to give it to them, not if they were going to arrest him. Although, to be fair, Doug could use a few nights in the nick. Warm, comfortable, fed and watered. Off the booze.

“What’s he done?” she asked.

He frowned. “Could you answer the question, please?”

“I’m not sure I want to.”

There was something about his face that she liked. The sincere, no-bullshit expression. The direct gaze.

“Why not?”

“Because he’s my friend.”

“And you don’t want to rat out your friend?”

“How can I rat him out when I don’t know what he’s done?” Shrap kept her voice even.

Trevelyan studied her, taking in her dishevelled state, her grubby clothing, her short, boyish hair. His gaze lingered on the faint bruise beneath her left eye where that moron Nico had kicked her when he’d tripped over her the other night. Shrap wondered what opinions he was forming. Abused wife? Homeless drunk? Addict?

Shrap shifted in her seat. If she’d had some warning, she’d have showered and washed her hair. Maybe even got a change of clothes. Nobody was supposed to see her like this. That was the whole point. She wanted to be invisible.

Not much she could do about it now.

He leaned back in his chair. “Your friend may have witnessed a crime.”

She wasn’t expecting that. “What kind of crime?”

“I’m afraid I can’t give you the details of an ongoing investigation.”

Another standard response. How many times had she used that line herself?

“This where it happened?” She tapped the CCTV photo with her fingernail, conscious it was dirty and jagged. She put her hand back in her lap.

A pause.

“Yeah.”

“Where is it?”

“Ufford Street, near Waterloo station. You know it?”

“No.”

He gave a deep sigh and leaned forward, putting his arms on the table. “This is an informal discussion, and you seem like a smart person. It would be great if you could give us some information about your friend. We just want to ask him some questions, that’s all.”

That was never all.

There was a long pause.

If Doug had been caught on camera leaving a crime scene, he was a suspect, not a witness. At the very least, a person of interest.

Shrap stared at the folder, wishing she had X-ray vision. What was Doug supposed to have seen?

Once upon a time she had believed in the justice system.

Trevelyan turned his hands upwards on the table. A gesture of trust. “Look, I’m just trying to find out what happened.”

She realised she still did.

“His first name is Doug,” she said. “I have no idea what his surname is, but he’s an old vet. Grenadier Guards, I think. You should be able to find out from that.”

He exhaled. “Thank you.”

She waited while he opened the folder and scribbled inside. He had long fingers, and she watched his hand glide across the page as he wrote.

He glanced up at her. “When last did you see Doug?”

“Yesterday morning at the day centre.”

His brown eyes narrowed. “Which day centre is that?”

She met his gaze. “The one that gave you my name.”

He looked down at the file. “Webber Street?”

She didn’t reply, it was all there in the file.

“What was he doing there?”

“Having breakfast. He’s there most days.” Shrap had also lent him a fiver, but she didn’t tell the DC that.

“What time does he usually go?”

“Nine o’clock, when they open.”

He checked his wristwatch, then reached into his pocket for his phone. “Excuse me a moment. I have to make a call.” He got out of his seat and turned his back on her.

She’d expected the move. Baxter and her pasty-faced companion were being sent on another mission.

Shrap glanced up at the cameras. One mounted on the wall behind him, the other in the far corner. Recording their every move. Feeding it back to a server that anyone with the right clearance could access.

“Hello, this is DC Trevelyan. Can you get Sergeant Baxter for me?”

She leaned forward and surveyed the open folder.

His notes were scribbled inside the cover in a neat, slanted hand. She didn’t bother with those; she already knew what he’d told her. What she wanted to see was the murder docket.

Victim’s name. Photograph. Occupation.

Trevelyan issued the order. “The day centre. Yes. Nine o’clock.”

She read it upside down. Slowly. Squinting to make out the name.

Bianca Rubik.

Blonde, sexy, short skirt, high heels. A soft face with hard eyes, and a seductive pout.

I can do things you only dream about.

Occupation: Sex worker.

Cause of death: Possible strangulation.

Which meant the post-mortem hadn’t been done yet. She leaned back, arms folded across her chest.

Trevelyan hung up the call. “Right, where were we?”