Ian opened his mouth, but Joanne put her hand on his arm, silencing him.

‘I want Ms Graham to pay for what she did and why she did it. I don’t want to do that by framing her for a crime she didn’t commit. How would that be any better than what she did to me?’

‘So why did she do it?’

‘Pardon?’

‘Why did Ms Graham frame you for the murder of your child?’

Joanne winced as if Nell had slapped her.

‘You’d have to ask her that.’

‘I’m asking you.’

‘Because she found proof, Sergeant, proof that gave her crimes away.’

Nell felt adrenalin kick in. ‘Crimes?’

When Joanne remained stoically silent, Paul took over.

‘Joanne, what did Mary say to you on the phone?’

Joanne hesitated before answering, clearly deciding whether to admit her role or stick to denial. She chose the former.

‘She said nothing. I asked if it was her, but she didn’t reply.’

‘But you thought it was her?’ Paul asked.

‘Yes. She’s done it before.’

Nell made a mental note to get Carla to check further back on Joanne’s phone bills.

‘So you’ve spoken to Mary before?’ Paul continued.

‘No. But I have spoken to her husband. And I think Mary has called me. I get odd late-night calls when no one speaks.’

‘You never told me that,’ Ian said, lowering himself onto the seat next to her. Nell held up her hand.

‘You’ve spoken to Mary’s husband?’

Joanne looked frustrated she had to explain. ‘Mary isn’t yet ready to speak to me, so her husband does.’

‘What were the conversations about?’

‘Just chatty, asking how I was, that sort of thing.’

‘And you contacted them?’

‘Yes.’

Paul glanced at Nell, who nodded for him to continue.

‘And why was that?’

‘Because Mary and her husband saved me – they’re the reason I’m alive.’

Nell couldn’t believe she hadn’t seen it coming.

‘Joanne,’ Nell said, ‘did Mary save you from the beach?’

Joanne looked at her. ‘Yes.’

‘Was your mum called Aoife?’

‘Yes. I just wanted to find out who had saved me, so I searched all the papers for clues of an abandoned baby around the time I was born, but the only thing I could find was a reference to a missing baby. I did look everywhere for more information and finally found a mention of a policeman who had looked after me the night I was born. I traced him to Thames Valley but when I contacted him and asked about Mary he explained she wasn’t ready to acknowledge her role in my mum’s death, so we were biding our time, trying to coax her to face up to her past. And mine.’

‘Joanne,’ Nell leaned in again, keen to get her full attention, ‘did you collude with Mary to kill Connor O’Brian?’