There had been a bottle of vodka, I said. I’d bought it myself – reluctantly – and on Scott McKenzie’s express instructions. Scott had big plans for the disco that night, and had suggested bringing a few little extras to (as he said) liven up the party a bit. I’d taken this to mean drugs and alcohol; which was why I’d chosen not to go rather than betray my lack of enthusiasm for his plan.

I admitted that I’d known it was wrong. I should have spoken up at the time; but I’d been afraid after the rocket incident, and had gone along tacitly with their plan, fearing possible repercussions.

As it happened, something must have gone wrong. Scott didn’t know very much about drugs, and I guessed he must have overdone it. I wept a few crocodile tears at the thought; listened earnestly to the officer’s lecture; then looked relieved at my lucky escape and promised never to get involved in anything like that, ever again.

It was a good performance, and it convinced the police. But my mother had her doubts all along. Her discovery of the peg-dolls did much to confirm this, and she knew enough about the properties of the substances in which she dealt to have more than an inkling of whom and what.

I denied it all, of course. But it was clear she didn’t believe me.

People could have died, she kept saying. As if that hadn’t been my plan. As if I cared, after what they’d done. And then she began to talk about getting help – about counselling and anger management and maybe a child psychiatrist—

‘I never should have taken you to Mexico City that year,’ she kept saying. ‘You were fine till then – a good little girl—’

Crazy as a coot, of course. Believing in every crackpot notion that came her way, and now, this growing delusion that somehow the obedient little girl she’d taken to Mexico for the Día de los Muertos had been taken over by some evil force – something that had changed her and made her capable of these terrible things.

‘The black piñata,’ she kept repeating. ‘What was inside? What was inside?’

But by then she’d grown so hysterical that I hardly knew what she was trying to say.

I didn’t even remember a black piñata – it was such a long time ago, and besides, there were so many in the carnival. As for what was inside – well, sweets, I suppose, and little toys, and charms, and sugar skulls and all the usual things you’d find inside a piñata on the Day of the Dead.

To suggest that it might have been anything else – that perhaps some spirit or little god (perhaps even Santa Muerte, greedy old Mictecacihuatl herself) had entered me during that Mexican trip—