Bannerman made short work of interviewing Frankie and then Joe but it wasn’t difficult: they had no evidence, no witnesses against them, nothing concrete to ask about at all. It was a fishing expedition. Since it was so late he took twenty minutes for each of them, asking them where they had been on the night of Sarah’s murder, who could confirm it, what they were wearing that night, had they ever been to their mum’s work, where they thought the ashtray, the eggcup and the watch had come from.

Both boys had been in for the early part of the evening and out for the second part, and since they couldn’t definitively say what Sarah Erroll’s time of death was, it left them as possibilities. Neither had heard of any money in the house.

McKechnie had pissed off home but Morrow and McCarthy stayed in the viewing room and watched Kay sitting next to Joe first and then Frankie. They saw her pretending to be calm for her boys, as if it was routine for them to be questioned in the middle of the night about a brutal murder. A couple of times when they looked afraid, she repeated the same phrase:

“They just need to know it wasn’t you, son, so they can find out who it was.”

But even on the grainy camera set high up on the wall, she didn’t look as if she believed it.

Joe came over very well. He met Bannerman’s eye and tried hard with Gobby, addressing his answers to him a couple of times, failing to draw him out of himself.

Frankie was younger by a year but a lot less mature. He was frightened and met the questions with a sulky glower, needing to be prompted by his mum several times. He should have been more forthcoming because he was the one with the alibi: he’d been at work, delivering pizzas, sitting in a car with a fat guy called Tam all evening. They needed two guys because Tam was the shop owner’s brother-in-law, needed the job, but was too fat to walk up stairs, so he gave Frankie a portion of his wages to do the leg work. Frankie made ten quid a night and got a pizza at the end.

By the end of the interviews, as Bannerman was telling Frankie and Kay that he’d need to see them all again but they were being sent home tonight, Morrow knew in her gut that they were innocent. Morrow knew what a cover-up among family members looked like: no eye contact between them, well-rehearsed answers to the important questions, often phrases echoed from person to person. When people were colluding no one had to check their phone or ask their mum where they had been on the night in question.

It was midnight when Bannerman shut off the tape and ejected it, bagging it for evidence. McCarthy went down the corridor to show Kay and her boys out, leaving Morrow watching the remote screen herself.

Bannerman and Gobby stood up and stretched their legs, pulled their jackets off the back of their chairs and gathered their papers. McCarthy was waiting by the door but Kay put her arm around Frankie’s shoulders and made him stand up. “What happens now?” she said.

Bannerman was magnanimous. “You can go home.”

“How can I go home? I left my purse on the kitchen table.”

Frankie looked at her. “I’ve got my Zone Card, Mum.”

“But that won’t get me home, will it? Or Joe.” She looked expectantly at Bannerman. “How am I to get home?”

She wanted a lift home. They’d never give her one.

Bannerman had his jacket on and was halfway out of the door. “Can’t you get a minicab and pay when you get to the other end?”

McCarthy touched her elbow, nodding her out.

“I’m eight floors up, they’ll not let me out the cab.”

“Send one of the boys up and you can stay in the car.”

Bannerman and Gobby jostled past her, bully-buffeting her and Frankie as they made their way out into the darkness of the corridor.

Morrow turned the car radio off. She was flying to London in the morning, catching the six-thirty flight, and should just go home, but she couldn’t just drive past them. It was a wild area. Blank walls were punctured with dark alleys and feral bushes grew over bits of wasteland. It wasn’t a place to walk at night. She saw them, one boy on either side of Kay, walking down the dark road, Kay’s head hanging forward, shoulders slumped low and Joe nudging his huddled mum and making a joke. They were taking the straightest path to walk the four miles to Castlemilk. Kay didn’t have taxi fare.

Morrow drew up ahead of them, pulled on the handbrake. She shut her eyes for a moment’s respite. This wasn’t going to be nice.

When she opened her eyes again she saw Joe looking in the window at her, frowning. She nodded to the back seat. He stood up and consulted with his mother in a whisper. Kay bent down then, glared in, angry and wet eyed, and stood up again. She told the boys something.

Frankie opened the passenger door and leaned in. “What do you want?”

“I’ll run you home.”

He slammed the door but they didn’t walk away, they were whispering. Morrow watched Kay’s hands adjust her handbag strap across her shoulder.

The back door opened and Joe got in first, climbing along to the far window, then Kay, then Frankie. He shut the door and they all pulled their seat belts on, managed to find the clips for them, though they were squashed up hard against each other.

No one spoke before Rutherglen. Morrow was afraid to look in the mirror. She wanted to put the radio on but was afraid a cheerful song would be playing and it would make her seem even more callous.

Finally Joe snapped, “This is good of you.”

Kay whispered, “Shut up.”

“But it is, Mum, it’s decent of her.”

“Nasty fucking arsehole.” Kay didn’t specify exactly which person in the car was the nasty fucking arsehole, but she didn’t need to.

It felt like a very long drive. Kay was crying at one point, sniffing, careful not to make too much noise. Morrow checked the mirror out of long habit and saw the shadow of Frankie’s arm moving over his mum’s shoulder. She looked away. She could be home now. She could be in her warm bed with Brian, sorting it out in her head, coming up with justifications, convincing herself that she was just doing the job, that she needed to make these hard choices for Sarah.

When they finally arrived at the steps from the main road to the high flats Kay said, “Here’s fine,” as if she was in a minicab.

Morrow was too tired to fight so she said nothing, drew up the hill and stopped.

Frankie opened the door and climbed out before she even had the handbrake on. Kay followed him. It wasn’t in Joe’s nature to leave without saying something.

“I do think that was decent of you. Thanks.”

Morrow didn’t wait to watch them open the door to the lobby. She pulled out and drove away, a little too fast.