Sasha’s eyes filled with tears. He hid it from everyone at school, because his dad told him he deserved it, that having to take care of Leon was the reason his mum became ill and died. I still wonder how none of us picked up on it. We thought the changes in his behaviour and attitude were because of grief, and he was at a transition point in his education as well. It got worse in the holidays, and that’s when Leon snapped. His dad had cornered him in his bedroom, but he always carried a pocket knife and Leon managed to get hold of it. He gave his dad a nasty gash on the arm, then ran next door for help. The neighbour called the police and an ambulance.

Forest and Singh both sat back when Sasha mentioned the knife and a chill ran through me. Hadn’t Forest said that a penknife was found near Steve’s body, and they presumed it was the murder weapon? Did this mean Leon could actually have killed his teacher?

After a moment, Singh asked another question.

‘Was his father badly hurt?’

Not at all, Sasha said, her face suggesting she wished he had been. It was only superficial. But Leon broke down when he spoke to the police, told them about the abuse, and the doctor’s examination showed he’d sustained multiple broken ribs over the course of at least six months, as well as an awful lot of bruising. His father’s lawyer tried to suggest that Leon had stolen the pocket knife earlier on in the week, making it a premeditated attack, but there was no evidence against Leon.

The detectives and I sat in silence for a moment. I couldn’t imagine what Leon had been through, losing his mum only to be handed over to a monster.

‘Thank you, Sasha,’ Forest said eventually. ‘Is there anything else you can tell us about Leon and the state of mind he might be in at the moment?’

No, I’m sorry. Except, he had become a little more secretive of late, keeping his phone close to him all the time and never letting anyone go near it. I know you’re trying to access his messages, so there might be something on there that can help you.

The DI thanked her again and asked her to fetch Bradley so they could talk to him. As Sasha left the room, she looked back at me for a split second, then closed the door behind her.

‘Bloody hell,’ Forest exploded, slamming her chair against the wall. ‘How did we miss that? Surely someone should have looked into Leon’s background and shown us that he attacked his dad with exactly the same weapon his head teacher was murdered with?’