Graham laughed and leaned on the counter, so I knew the interview was finished. He took his meds like a child collecting a prize. He said, ‘Thank you, George,’ and marched away without looking at me.

I stepped forward to take mine, then moved quickly away.

‘No, thank you,’ George said.

L-Plate was next in line, so I lingered while she picked up her pills. Just your basic anti-depressants and stuff to combat the withdrawal. Methadone or whatever. I knew that, because she had an injection once a month for the heebie-jeebies.

I can’t stand needles, so I’ve always opted for the tablets. Sometimes, if I’m lucky, I’ll get oral dispersibles, which are basically just these wafer-thin squares that melt on your tongue. Yum!

I collared her as soon as she stepped away from the hatch.

She raised her hands. ‘Too close . . .’

‘Sorry, L.’ I raised my own hands in apology and moved back a little. ‘I just wanted to ask you . . . I heard that you know what started the big fight a couple of days before Kevin was killed.’

‘Heard from who?’

‘It doesn’t matter, honestly. Something about a row between Kevin and Shaun?’

‘Oh, that, yeah.’ Lucy leaned back against a wall and began doing weird stretches, like she was practising some kind of psych-ward t’ai chi. She was wearing a Calvin Klein T-shirt and tracksuit bottoms same as me, only I was damn sure she hadn’t bought her trackies at JD Sports. ‘Well, to be honest I didn’t hear very much, babe. They were shouting at each other after the last occupational therapy session. I was only in there because I wasn’t very happy with what I’d painted that day and I was trying to tidy it up a bit.’

‘What were they arguing about?’

‘I wasn’t trying to eavesdrop or anything. I mean I really wasn’t, so I just caught snippets of it. There was something Shaun wanted Kevin to do and Kevin wasn’t keen. Shaun was telling him he had to, that he was being stupid . . . that was about it.’

‘So that was what the fight was all about?’

‘Who knows what started that,’ Lucy said. She stopped the stupid stretching and leaned as close to me as I ever saw her get to anyone. ‘You think it had something to do with why Kevin was murdered? A grudge or whatever?’

‘I’m trying to piece it together,’ I said.

She put her arms up, stretching her fingers towards the ceiling tiles, then cocked her head to whisper, ‘I’d heard it was a drugs thing, and I have to say that wouldn’t surprise me. Obviously, you know my history, right? Well, the fact is, one does learn to recognise it in other people.’

I knew what she meant. Like coppers knowing when someone was iffy.