‘That’s a bit more tricky. The outside temperature was sub-zero – I understand it hit minus ten on a couple of nights – and it was only marginally warmer inside the hut, which gave minimal protection from the extreme cold. She was very close to being frozen, although not enough to stop all decomposition. Based on those factors, I’ve tried to come up with a timescale, but there are so many variables that could affect it. On balance, I would say she died either immediately before the freeze or within the first two to three days of it. Had it been earlier, more decomposition would have taken place. Sorry – that’s as precise as I can make it.’

‘She died in the hide, you believe, so that’s a help.’ Tom mulled over the options, speaking them out loud to try to make sense of them. ‘If she arrived after the start of the freeze, it had to have been on foot, given that the park area was closed to traffic. Even if we ignore the lack of shoes and coat, both of which could have been discarded, it would have been a difficult walk in those conditions. On the other hand, if someone took her there by car and left her, whether to die or not we don’t know, then it has to have been in the few hours before the freeze set in.’

‘That just about sums it up,’ Amy said. ‘There’s something else I would like to run by you, though.’ She beckoned him a little closer. ‘You mentioned slight cyanosis, and you were right, but as you and Jumbo noted there is no sign of any violent act. Even if she had been smothered with a cushion you would have expected her to put up a fight – unless she was drugged, and we won’t know that until we get the tox results. But possibly more relevant is the fact that there weren’t any fibres in her mouth or her nostrils.’

Amy pointed to the woman’s neck. ‘She wasn’t strangled, but if you look very closely, there is evidence that something was tied around her neck. Not tight enough to asphyxiate her, but tight enough, and there are one or two places that look as if something was rubbing on the skin before death. See here…and here.’

Tom looked at the marks and then back at Amy. He had no idea where she was going with this.

And then she told him.