The vague image of Orsu as a baby in his pram, under the holm oak at Arcanu Farm came back to her. A calm and quiet baby. Clotilde had been fifteen at the time, and hadn’t paid the baby any more attention than if he’d been a doll.

The question burned Clotilde’s throat, it gnawed like acid.

‘Does anyone … does anyone know who Orsu’s father was?’

A question to which she already knew the answer.

‘It’s an open secret,’ the policeman replied.

He forced a laugh. With each movement of his neck or his arms, the damp fabric under his armpits stuck to his skin then came away again.

‘But an open secret that no one likes to talk about. That’s why I wanted to talk to you here. Because of his various imprisonments for actual bodily harm, Orsu’s details have been held on the national DNA database. It wasn’t hard for me to check the rumour that had been circulating since he was born.’

Get it over with. Was the old policeman finally ready to drop his bomb?

‘I think you’ve already guessed, Clotilde, unless you remember. There is no doubt about it – you and Orsu share a father. Your father had this child with Salomé Romani, Speranza’s daughter. The child was conceived in August 1988 and was born on 5 May 1989. He would only have known his father for two weeks, sixteen days to be precise. Although “known” is a generous word – Paul was married, married and the father of two older children, Nicolas and you. I’m not even sure that Paul ever met him, or acknowledged him, or was even aware of the child.’

Distant images whirled through Clotilde’s mind: a spiral staircase, a lighthouse, a baby in her father’s arms. Images she had repressed so often, but never forgotten, filtered out, perhaps. Like a story with some pages missing. The last in particular, the ones that would explain everything.

‘He … Was Orsu born disabled?’

‘Yes. Salomé didn’t want to keep him, but the Romani family don’t have abortions, they’re as Catholic as they come. So she tried to tolerate him, as they used to say in different times. You know, like in Manon des sources, when Papet asks at the end of the book, “Was he born alive?” “Alive, yes, but hunchbacked.” One of Orsu’s arms was paralysed, and one of his legs, and part of his face too, and probably part of his brain, the part that governs language.’

Orsu? Her half-brother? Clotilde couldn’t grasp it. She felt as if her brain was on automatic pilot, appealing to her pre-conditioned professional reflexes: she had to concentrate solely on the murder of Cervone Spinello, she would deal with everything else later, only then would she wonder about the implications of having a half-brother in her life.