Returning to the front room, he found her in a calmer state. Her eyes were clearer, and she hardly trembled at all. The smell from the vomit on the carpet was bearable, and she seemed to have forgotten about it entirely. In fact, she looked almost serene.

He sat down again, tried to think of sensitive words, something kind to say. Nothing came. And meanwhile, he wanted information. More than anything, though, he wanted to be away. He was buzzing for the first time in years, desperate to get the case moving, to feel the urgent, unsettling thrill of going after a murderer.

‘These people who were threatening Craig. Any idea who were they?’

‘Dunno. They never said. They’d phone here, send stuff. Dog shit in a jiffy bag.’

‘You saved any of the envelopes?’

‘No. Binned the lot. No idea who they were.’

‘Rival dealers?’

She said nothing. But she didn’t disagree. Her silence made it all so banal. Craig had been killed, burnt to a cinder, because someone else wanted to sell drugs to teenagers in small northern towns with funny names. Someone wanted to take his sordid, small-time place in the world, and it was worth murdering for.

‘He was doing his best,’ she said.

Joe stopped, wrote the sentence down. He was doing his best. That was one to come back to.

‘Lisa Cullen. Yesterday you told me you didn’t know her. Why?’

Her face held steady for a second, perhaps two. Then she cried. He watched as the tears raced down her cheeks. He felt a wave of sympathy, a sudden, urgent loathing for the world. Then, immediately afterwards, a sharp sense of satisfaction: it had been the right question.

And at that moment, with the faint whiff of vomit in his nostrils, he knew why he’d become police. Because he was tenacious enough to do the right thing by a grieving mother, even if that meant putting her through this.

‘I were trying to keep Lisa out of it. Thought they might get her as well.’

‘OK. The photo was taken up at the university. Was Craig selling on campus?’

She looked shocked.

‘No. I took the photo. I went up there. She were trying to get me to sign up for a foundation course.’

‘Lisa?’

‘Aye. Helping me. She’s like that. She were helping our Craig, an’all.’

‘Helping?’

‘An angel, she is. A bloody angel.’

There was a knock at the door.

‘That’ll be victim support. I’ll let ’em in on my way out. And I’ll be in touch soon. In the meantime, there’ll be a team here to search the house and to interview you properly and take a full statement. That OK?’

She nodded.

But Joe had already gone.

10