Joe slides his phone into the back pocket of his jeans and releases a sigh of frustration, although Mr Packard not picking up his calls is hardly damning evidence of guilt. Of course the guy’s going to be pissed off with Mark after the idiot frightened his daughter half to death – Christ knows how Mark managed to get into her school at all; Joe has already briefed the school liaison officer about the incident – but that doesn’t mean the ex-public-school boy is going to slip out in the middle of the night and try to strangle a homeless teenager in a dirty squat. In reality, it’s much more likely to be a fight over the spice he clearly nicked – either the original owner wanting payback, or another addict taking issue with Mark’s little windfall. The older injuries that the doctor mentioned back that up, and as Joe looks around the squat, he’s even more inclined to think it.

‘Bit of a mess,’ Jason surmises, which is a massive understatement. There’s damage to the walls, flakes of plaster on the floor, and a huge, smashed mirror with shards of glass refracting in the sunshine. The only furniture in the room is an old IKEA sofa, dumped in the middle, but most of its cushions have been flung around the floor too. And the final addition to the smorgasbord of debris is a few dozen brightly coloured metallic packets, like football cards with added hallucinogenic. The last time Joe was here, it was night-time and he was in and out in a few minutes, and more focused on trying to caution a lanky drunk kid than taking in his surroundings. But his impression was that it was a fairly civilised place to bed down. It doesn’t look like that now.

‘Found anything useful?’ Joe asks Isobel, one of the two scenes of crime officers methodically working their way around the squat. The other one – Annie – is a county netball player, and the only woman Joe would consider marrying without a first date, so he tries to avoid conversation if he can.

‘No sign of forced entry at either the front or rear,’ Isobel starts, her voice quick and efficient. ‘But the back door wasn’t locked and there’s access from the road via the alleyway so no massive mystery there.’

‘Any other good news?’ Joe asks sarcastically.

Isobel gives him a look. ‘The five dents in the plasterboard over there look fresh,’ she says, pointing to the wall that runs from the front door. ‘And consistent with a kicking action.’

‘Suggesting a fight,’ Joe murmurs, but Isobel just shrugs; supposition isn’t her job.

‘The measurements suggest that all the dents were made by the same footwear,’ she continues. ‘Most likely a boot or heavy trainer.’

‘Interesting.’ Joe looks a bit closer at the wall.