"Yup." Maureen smiled. "I don't like that Joe McEwan character at all."

"Yeah, he's a total prick but don't let on you don't like him."

"Why shouldn't I?"

"He's a big noise up there. It could make a difference to how they treat you. Try to seem friendly," he said, as if he'd spent his life being questioned by the police. "They asked me what I was doing yesterday afternoon."

"Yeah," said Maureen. "They were asking me about the morning and afternoon. I guess that's when they think it happened. I was at my work."

"Yeah. I had a key and I can't tell them where I was during the day."

"Why not?"

"I was at Tonsa's seeing Paulsa."

Tonsa was a courier. She traveled to London on the train once a month, bringing crack to Glasgow. She looked like a well-to-do lady in her early thirties: she had elegant bone structure, a slim figure and expensive, stylish dress sense. Liam had introduced her to Maureen when they bumped into her at the Barras market one Sunday. She looked normal until Maureen noticed her eyes: they were watery and open a fraction too little, they were a corpse's eyes, Tonsa was dead beneath the skin. Until then Maureen had thought of Liam as the Gentleman Jim of the drugs world. After meeting Tonsa she realized there was no such thing, that Liam must be a heavy guy. But he wasn't like that with her and she hung on to that. He was her big brother, she reasoned, and she was entitled to censor his life for her own consumption.

Tonsa had been in the papers recently: her boyfriend had been slashed, ear to chin, while he went about his lawful business. The local paper carried a photo of the lovely couple demanding that the police catch the evil men responsible. At the time Maureen had asked Liam why Tonsa let them take her picture, surely she wouldn't want that sort of attention. Liam had shrugged and said Tonsa was wasted, no one knew why Tonsa did anything.

"Liam," she said, nervous at asking, " 'member Tonsa's man was slashed?"

He looked up at her. "Aye?"

"Well, that wouldn't be anything to do with this, would it?"

"What d'ye mean?" he said, staring at her, daring her to go ahead.

"I just wondered if you knew anyone -"

"Am I getting the blame for this?" he snapped.

"Right, you" – she wagged a finger across the table at him – "calm down. I'm not blaming ye, I'm just asking ye. It's not an unreasonable question. You're the only person I know who deals with these kinds of people."

"Yeah, well, Maureen," he said, trying to be reasonable because she'd had a shitty day, "we're not the only people who do that sort of thing. There are other bad men in the world."

"I know that, I'm just wondering, gangsters do that sort of thing, don't they?"

Liam smirked uncomfortably at the table. "You watch too many films, Maureen, these are businessmen… Ye don't get much of that sort of thing."

Maureen looked unconvinced. "Someone wouldn't be trying to send you a message? A warning or something?"

"Look, how does that send a message to me? Why kill my wee sister's boyfriend in her house leaving no clue as to their identity?"

"I suppose."

"If someone wanted to send me a warning they'd walk up and smash me in the face. It wouldn't be a secret, I'd know I was out of line and I'd know it was coming. These people are motivated by greed. They don't want trouble with the police – that just makes it harder to do business."

"Right enough. I just thought, because of the slashing…"

"Slashing people's faces, that's something trainee neds do to show their mates they're hard, they don't even know the person they're doing it to, they just run past the person and-" He flicked his wrist in a way she found worryingly dismissive.

"You've never done that, eh?" she asked timidly.

"Don't be ridiculous." He was staggered at the suggestion. "Do you think I'm capable of that?"

"Not really."

"Mauri, do you really think I'd do that to someone?"

"Auch, no, Liam, no. But I know you're protective of me since I was in hospital."

"Protective?"

"Yeah, protective."

"And I'm stupid enough to think carving up your boyfriend in your own living room is going to protect you from something much worse? Like what? Like falling out with him?"

"Aye, right enough."

"Anyway." He smiled at her. "I'd hardly do it when my alibi would get me arrested, would I? I'd be smarter than that, anyway."

"Auch, I'm sorry, Liam." She smiled back at him. "I'm a bit bewildered today."

She cut a bite out of the bridie and put it in her mouth. It hadn't been microwaved properly and undissolved fat still clung to the slimy inside of the cold pastry wall. She bit down onto a lump of gristle and made a face. "That's disgustin'." She spat it out into a napkin, wrapping it into a little bundle and putting it in the ashtray. Her appetite was gone.

"I'm so fucked," said Liam. "I can't tell them where I was."

"It might have happened at night. That time-of-death stuff isn't a set science, it's just a good guess."

"Did the police tell you that?"

"No," she said. "But the heating was on in the house this morning- it was belting out. I wondered if that could change a time of death."

"How?"

"Well, they work it out by comparing the temperature of the body to the surrounding temperature. What would it be if the person was alive – say, ninety-eight point six degrees?"

"I dunno."

"Anyway, what if the surrounding temperature wasn't constant? That would change the rate of heat loss. What if the heating was turned right up and set to go an hour or so before he was found? That would heat up the house but wouldn't be enough to heat up a body. The police would take his temperature thinking he'd been in a warm house the whole time he'd been dead. They'd think he'd died earlier than he actually did."

"Maureen, what are you rambling about?" said Liam seriously.

"They could have got the time of death wrong. It could have happened in the evening."

He looked confused. "Wouldn't the police think of that, though?"

She shrugged. "Yeah, but even if they did it would still be hard to work out the times: they couldn't know what the temperature had been before the heating went on."

"And did it occur to you that if the murderer did that deliberately they'd need to know how the police work out the time of death? Where did you hear all that science stuff anyway?"

"I saw it on Taggart"

Liam giggled at his plate. He could tell he was making Maureen angry but couldn't stop himself. He put his hand over his mouth. "I'm sorry, Mauri-"

"Yeah, fuck you."

"Yeah." He sniggered. "Okay, fuck me."

"I read it in the paper as well, Liam."

"So it must be true."

"What were you doing that night?"

"I was with Maggie at her mum and dad's."

"And were they in?"

"Yeah."

"Well, if I was right they could vouch for you."

He grinned at her as if she was mental. "Okay, Dr. X."

"Don't take the piss, Liam."

"I'm trying not to but you make it so hard." Maureen looked downcast.

"Did you tell the police that?"

She looked even more miserable. "I tried," she said.

He suppressed a smile. "And what did they say?"

She didn't answer him.

"Well," he said, jabbing at a chip, "I'm sure they'll find whoever did it soon enough. Buccleuch Street's always busy. Someone must have seen something."

Maureen picked at her chips. They were soggy, limp and warm. She should eat something. "I don't know why I keep coming here, the food's horrible."

"Good fry-ups, though," said Liam.

"Did they tell you anything about the cupboard?" she said, trying to catch the waitress's eye. She limped over to their table. Maureen ordered an ice cream and a coffee. They looked to Liam for an order. He was eating his chips eagerly now, spearing three at a time with his fork and swirling them around in the mess of ketchup on the side of the plate.