‘It’s the latter, I believe. Look at this.’ She turned the corpse’s left arm outwards to display the incisions more clearly. ‘The callusing on Mrs Hawksmith’s right hand is indicative of a right-hander. Over the years, the hardening of the skin on the ends of the fingers and the palm leaves its mark. Writing, cutting vegetables, picking things up, opening jars, you name it. Also, the muscles of the dominant hand are always fractionally more developed. Now look at the cuts.’ Ailsa pulled a mobile light over the top and swung a magnifying glass to highlight the gashes. ‘The deepest end of the cuts is on the inner elbow nearest the body, moving from the right side of the inner elbow to the left. When you compare the blade, it has a flat edge on one side and that flat edge was inserted closest to Mrs Hawksmith’s core.’

‘So the blade would have to have been pushed outwards rather than have been pulled towards her body,’ Ava noted.

‘Which isn’t natural at all. You’re taught to write pulling the pencil towards you. You cut food pulling rather than pushing. It’s inconceivable to me that she started the cut on the inside of her arm and pushed to the outside, not least because she’d have been holding the knife with the blunt side of the blade inwards, which doesn’t fit with a right-hander.’

‘Someone else made the cuts,’ Ava said.

Ailsa nodded. ‘It’s not that she couldn’t have done all of this to herself, don’t misunderstand me, but it makes no sense at all. None of it. And as for where the blade was found …’

‘It’s a debasement. Signs of sexual assault?’ Ava queried.

‘No evidence at all. Neither vaginal nor anal. There’s no tearing or injury; although fluids might have disappeared, as she was sat in the water for so long before being found. We’ve taken swabs for DNA tests but I’m not expecting anything.’

‘It’s a very personal thing to do and I don’t mean physically. It suggests anger at a deeply personal level, wanting to degrade a dying woman like that. There would have to be a specific motive,’ Ava said.