Mackey didn’t argue. Probably Conway thought that meant she’d won. He wandered off around the room, past the chair we’d set out for him, having a look at the art projects. Gave Holly’s hair a quick rub on his way. ‘Do us a favour, sweetheart. Before you answer any of the lovely detectives’ questions, give me a fast rundown of what we’re doing here.’

Shutting her down would wreck the vibe right there. Conway’s look said she was starting to see what I meant about Mackey. Holly said, ‘This morning I found a card on the Secret Place. It had a photo of Chris Harper and it said, “I know who killed him.” I took it to Stephen, and they’ve been hanging around here all day. They just keep interviewing all of us and all of Joanne Heffernan’s idiots, so I think they narrowed it down to one of us eight must’ve put the card up.’

‘Interesting,’ Mackey said. Leaned over, examined the wire school from different angles. ‘That’s coming along nicely. Anyone else’s parents get brought in?’

Holly shook her head.

‘Professional courtesy,’ Conway said.

‘Makes me feel all warm and squishy,’ Mackey said. He pulled himself up onto a windowsill, one foot swinging. ‘You remember the deal here, sweetheart, am I right? Answer what you want to, leave what you don’t. You want to discuss something with me before you answer it, we’ll do that. Anything upsets you or makes you uncomfortable, tell me and we’ll make tracks. That all sound OK?’

‘Dad,’ Holly said. ‘I’m fine.’

‘I know you are. Just laying out the ground rules, so everyone’s clear.’ He winked at me. ‘Keeps everything nice, amn’t I right?’

Conway swung a leg over her chair. Said, to Holly, ‘You are not obliged to say anything unless you wish to do so, but anything you do say will be taken down in writing and may be used in evidence. Got it?’

You try to keep it casual, the caution, but it changes the room. Mackey’s face giving away nothing. Holly’s eyebrows pulling together: this was new. ‘What . . . ?’

Conway said, ‘You’ve been keeping stuff to yourself. That makes us get careful.’

I took my seat, opposite Holly. Held out a hand to Conway. She sent the lost-and-found phone, in its evidence bag, shooting down the table.

I passed it over to Holly. ‘Ever seen this before?’

A puzzled second; then Holly’s face cleared. ‘Yeah. It’s Alison’s.’

‘No. She has one the same, but that’s not it.’

Shrug. ‘Then I don’t know whose it is.’

‘That’s not what I need to know. I’m asking if you’ve seen it before.’

Longer puzzled look, slow head-shake. ‘Don’t think so.’

I said, ‘We have a witness who saw you drop it in the lost-and-found bin, the day after Chris Harper died.’