‘We can’t be sure of that yet. He was so enraged when he realised Elspeth wasn’t the pure and untainted specimen of a wife he’d envisaged that he became irrational. If he wanted Elspeth as a wife, then maybe he also wanted Meggy as a daughter.’

‘Why does a dead man need a family?’ Baarda asked.

‘Maybe he’s scared of the sense of invisibility he feels. Don’t we all just want to be remembered, to be missed by the people who loved us most, when we die? Perhaps that would make the end of his life more bearable,’ Connie offered. ‘That could be why his victim type has varied so greatly. They’re playing individual roles. It’s part of a larger scheme.’

‘If Cotard’s syndrome covers anything from believing you might be dying to deciding you must be immortal, how do we know what stage his symptoms are at?’ Baarda asked.

Connie referred back to the text on the screen. ‘This says the syndrome has three stages. Germination, where symptoms of hypochondria and psychotic depression become apparent, although depression may pre-date all symptoms, of course. Then there’s the blooming of the delusion of negation, where the sufferer becomes more aware of the change in their body, the loss of a part of themselves or their whole existence. Finally, there’s the chronic stage, where the delusions are at their peak. You’re looking at schizophrenia mixed with psychotic depression. Chronic sufferers will be unable to distinguish reality from delusion, may not recognise the world around them and will be unable to maintain normal relationships. Physical health, hygiene, the simplest of interactions will become impossible to maintain.’

‘All right,’ Baarda said. ‘Practically speaking, if you’re right about this, how does it help us find him?’

‘I need broad access to health-system workers in the wide geographic area. Is there a system for putting out an alert?’

‘I can organise that,’ Baarda said. ‘What are you going to do?’

‘I doubt he’s been diagnosed if he’s still in the community, but there will have been physical symptoms, and some indicators of a patient struggling with their physical and probably mental health. Give me half an hour? I’ll put together a list of likely symptoms, which we can combine with the broad physical description we have. I’d like to see if there are any mental health workers, primary carers, hospital staff, or community support specialists with whom this rings any bells. This didn’t come on overnight. If he suffered from a high level of hypochondria and depression in the early stage, there’s every chance he sought help.’

‘What might have caused it?’

‘Could have been anything from a brain atrophy to a tumour or an accident causing damage. Most cases come from frontal lobe injury, such as resulting from seizures,’ Connie said.