Ailsa glanced sideways at Connie. ‘I cannot,’ she said. ‘That does not mean it has never happened; nor does it mean that this must be the first case of its kind.’

Connie got to her feet. ‘That’s all right, Dr Lambert,’ she said. ‘I’ll take it from here.’ She waited for Ailsa to sit, then took centre stage. ‘We know more about our killer than we realise. We have a good physical description. But we also know that he’s single.’

‘We haven’t established that,’ someone shouted.

‘Actually, we have. He was obsessed with Angela, who was the model wife. He didn’t want to kill her. That wasn’t part of his plan. When he found out that Elspeth had been unfaithful, he was distraught. He talked about Elspeth as if she were his wife. As if she’d been unfaithful to him personally. If our killer had a wife, or was in a successful relationship, he wouldn’t need to abduct a woman to play that role. He might be physically off-putting to women, which fits with being emaciated and perhaps having poor hygiene, or he might make them instinctively feel ill at ease. Either way, it fits with Cotard’s syndrome. Furthermore, a close-knit family might well have reported their concerns by now to a doctor, or even to the police. So we can also assume he lives alone, has accommodation that he doesn’t share, has access to a vehicle that he doesn’t share, and has an income that doesn’t require him to work.’

‘Disability benefit?’ Baarda suggested.

‘That would fit. The weight loss alone would be enough to concern a doctor, and he would likely be suffering additional symptoms, such as regular migraines from the failure to eat, low blood pressure, anaemia, bowel and stomach problems. Regular work would be unsustainable.’

‘He killed Danny Taylor in cold blood. The witness reported that he hardly seemed to notice what he was doing. If he’s not a psychopath, how can you explain that?’ Overbeck demanded.

‘I didn’t say he’s not a psychopath,’ Connie corrected. ‘It’s possible that he is. Statistically speaking, enough cases of Cotard’s syndrome have now been reported that sooner or later, a sufferer is also going to have other mental health conditions, and then all bets are off. But I think Danny’s death indicates something else. At its most developed, Cotard’s syndrome is an absolute delusion. It’s world-destroying. This is perhaps the only time when it’s helpful to refer to it by the name walking corpse syndrome. Imagine believing you’re dead. I mean, truly being immersed in that belief. What stops you from killing at that point?’

‘My humanity,’ someone offered.