Morrow walked up the ramp to the door, stopped outside, looked straight into the camera, and punched in the door code. John was behind the processing bar, always immaculately uniformed, leaning his weight on a tall stool preserving the creases in his trousers.

He bid her good morning and she gave him a smile. She pushed through the door to the duty sergeant’s lair and saw Omar and Billal through the striped window, sitting on the visitor’s chairs by the front door, waiting. Their postures didn’t match: Billal was upright, his arm around the back of the chair, his expression hurt. Omar was slumped over his knees, his mouth pressed hard into his hand, holding in a scream.

The senior duty sergeant, Gerry, grunted an acknowledgement at her and went back to filling out some time sheets. Morrow had been on at weekends when fights broke out in the waiting room and had seen Gerry plough into a crowd, peeling the drunks off one another like a surgeon easing skin back, never breaking a sweat. Gerry’s hair seemed whiter every time she saw him. They kept starting new trainees but it would be a rare copper who could follow Gerry. The blend of meticulous form-filling and sudden violence took a particular kind of man.

She grunted back and opened the door into the lobby. Omar and Billal recognised her. Omar stood up, hopeful she would take him away from his growling brother.

‘No,’ she raised a hand, ‘I’m not here to get you guys, I’m not doing the questioning, just going in here.’

She backed off to the CID corridor on her left. She punched in the security code and opened the door, glad to get into the long green corridor. MacKechnie’s office was at the far end, so he could stand at his door and look down at all of them. He never did.

The clarity of rank structure was one of Morrow’s favourite things about the force. She knew who she had to take shit from and who she could give it to. It made sense to her. MacKechnie was not comfortable being in charge, she felt, and apologised for his status by pretending to listen. He had a leadership style that would be described with a lot of bullshit buzzwords: inclusive, facilitative, enabling.

Even at half three in the morning the corridor was relatively busy. MacKechnie’s lights were on, his door open, his office empty. An incident room was being set up next to the tea room. She could see two uniforms moving a table through, negotiating the legs around the door frame.

She walked into her own office, flicked on the light and dropped her handbag. Bannerman’s computer was on, his screen saver a photoshopped picture of himself on a body builder’s body. Hilarious. His mouse had purple lights on the underside that distracted her eye when she was working. He kept chewing gum and healthy snack bars in his desk drawer, afraid of getting fat, she thought.

Everything on Morrow’s desk was new and ordered and anonymous. A drawer of neat pens, a sharpener and spare jotters, always three, for making notes. She liked them new, threw them away once they had been used. She liked to think the desk could have been anyone’s anywhere, devoid of history, that she kept her personality out of it, bland as beige, how she liked it.

She was hanging her jacket up by the door when she saw Harris standing outside. DC Harris was small and coarse-featured, as if he’d grown up outdoors. He was likeable, had a flat Ayrshire accent and a perpetual look of surprise on his face: eyebrows raised, mouth in an open ‘O’.

‘Ma’am?’ He seemed excited. ‘Great, eh?’

‘Is it?’

‘Aye.’ He had probably been expecting a routine night but found himself confronted with an actual genuine mystery instead of depressing, go-nowhere domestics and drunks clubbing each other for the price of a packet of fags. ‘My piece break. Coming to watch?’

‘Watch what?’

‘Bannerman thinks the youngest son’s it. He’s getting him into Three.’

Bannerman had clocked her interest in Omar and she rolled her eyes without thinking, annoyed at herself for being so obvious. Harris saw her and misunderstood, remembered that it was supposed to be her case and felt bad about it. As a consolation he said, ‘Coming anyway?’

She chewed her cheek, tried to change her face from huffy to neutral, said, ‘Aye, fuck it,’ and followed him out of the door, past Billal and through the far door to the stairs.

They trotted up to the second floor, into a room that always smelled of vegetable soup.

Everyone on CID was on their piece break apparently. Orange plastic chairs were laid out in two ramshackle rows of four but they were full already. MacKechnie must have given them permission. A short DC stood up to give Morrow his seat in the front row and everyone else in the room lifted their arses off the chairs as she sat down, respecting the rank.

‘Yeah, yeah,’ she flapped a hand at them, ‘calm down, it’s not a parade.’

She could see them from the corner of her eye, sloping down in the chairs, not as they had been but relaxing within regulation stipulations, wary. It made her feel powerful. She kept her eyes on the boxy black television against the wall.

CID recorded their interviews and the cameras could be used as a feed to keep everyone briefed. Not everyone liked being watched though and it wasn’t always because they were bashful: some preferred to do an interview themselves and highlight lines of questioning themselves. It took a lot of balls to let other officers watch.

Morrow felt that being watched had forced a strange, strained quality on interview technique. Questioning was different now; guarded and formal and questioning officers were routinely respectful of even the lowest scrote. They spoke in a bizarre police-ese, as if they were giving evidence in court.

It never used to be this way. When she was younger Morrow remembered questioning as a drunken polka, officers and suspects swinging each other wildly around the facts, faster and faster, until something got broken. Now it was a strained quadrille where the rules of the dance stood hard and fast until one capitulated or the tension of the moves strangled the breath out of one of the participants.

Morrow thought people’s responses to being watched said a lot about their view of themselves: some enjoyed it, assumed a positive response from a viewer. Some couldn’t cope, froze, glanced at the camera and had to hand over to a colleague. Morrow felt she looked shifty on camera, guiltier than the crims she was interviewing.

The shot of the room was badly set up. It wasn’t there to capture the nuances of the suspect’s facial expressions but to prove that no one had been throwing punches. Because the camera was mounted high up on the wall the room looked narrower on camera than it seemed when she was in there, more claustrophobic. And the image was grainy, the colour drained from the room into a palate of grey and blue and yellow. A table with a wooden top, four chairs, a light switch and the door which had been left open slightly, the dusty top of it visible.

The door opened suddenly and Omar Anwar walked in. A muted cheer rose from the officers in the viewing room, muted because she was there, but it was as close to camaraderie as she had felt since her promotion and she found herself not exactly joining in but smiling along.

They liked that.

Omar sloped into the room as if he had extra vertebrae, hips first, bending like a question mark as he put his plastic tumbler of water on the table. Bannerman came into the room after him and some of his fans gave another cheer. Morrow didn’t concur with that one and felt them clock it.

A fat officer nicknamed ‘Gobby’ came in after them. Gobby rarely spoke. Bannerman had chosen him over her, she realised, so he could shine.

Someone at the back muttered to themselves, ‘The BannerMan’ll nail him.’ The nickname brought a sting of bile to the back of her throat.