‘Well, I don’t think anything was proven, but I can tell you now the Bovingdon surgery closed soon afterwards when word got around it was run by a vet who was prepared to kill on demand. If I’m honest, I may have had something to do with that. But the point is, Liz got her dog put down when it was as healthy as you or me.’

‘And you’re sure that’s what she did?’

‘As sure as I am of anything. It’s wicked. Crumble had such a lovely soul. Anyone would have taken him in if Liz didn’t want the responsibility. I’d have taken him. But that’s Liz. She’s a dog killer.’

Judith and Suzie lapsed into silence as they pulled into the little gravel parking area of the Marlow Rowing Centre. It was made up of a clutch of Portakabins and huts that had been built on the edge of town on a bend of the Thames. The setting was gorgeous, but the buildings were weather-beaten, and the red, white and blue canoes and kayaks that were stored in metal stacks had all seen better days.

‘You’re right,’ Judith said to Suzie as they got out of the van. ‘We could be about to speak to the killer. Are you sure you want to do this?’

‘Bring it on,’ Suzie said, and there was something about her blind enthusiasm that gave Judith pause.

She pulled her phone out and dialled Tanika’s mobile number.

‘Judith, are you okay?’ Tanika said as she answered the call.

‘I’m fine, thank you for asking. I just wanted to let you know I’ve worked out who the auburn-haired woman is. You know, the one I saw in Stefan’s garden. And in the field the day after.’

‘You do? Who is she?’

‘Her name’s Liz Curtis, and she runs the Marlow Rowing Centre.’

‘Are you sure?’

As Tanika asked the question, Judith saw the auburn-haired woman step out of a Portakabin with a paintbrush, shake the water out of it and then head back inside. She didn’t look over and so didn’t see Judith or Suzie.

‘Oh yes, I’m sure,’ Judith said.

‘Then you have to promise me something.’

‘What?’

‘You won’t try and investigate her.’

‘What’s that?’

‘Because you’ve already put yourself at risk once, when you chased that intruder in Stefan Dunwoody’s house. And I’m not having you do that again.’

‘I wouldn’t worry about that, it was very much a one-off.’

‘Because I don’t think the killer’s done yet.’

‘How do you mean?’

‘I can’t be sure, but I think there might be another murder. A third murder.’

Judith’s hand tightened on her phone. How could Tanika possibly know this?

‘So you have to promise me you won’t do anything to put yourself in danger? I want to hear you say the words.’