‘It’s unlikely that he managed to forcibly abduct all of these women without anybody spotting some sort of commotion,’ she resumed. ‘That would lead me to believe he either spied on his victims for a period to establish their routines and then snatched them when they were alone, or he was able to entice them to go along with him. You should speak to the woman you think was an attempted abduction earlier this year and see if her being outside that pub on her own late at night was a regular occurrence. Did she go there every Friday and usually walk home alone, that kind of thing?

‘He’s probably handsome, or has a harmless appearance. He might wear glasses. Women tend to find men wearing spectacles less threatening. Or perhaps he’s a professional of some kind – a doctor maybe, somebody who can get his hands on a uniform that women find reassuring.’

Linda hesitated, her writing hand poised mid-air.

‘If Fiona Holland was taken to compensate for him missing out on that intended sixth victim last spring, then he has deviated from his usual routine. Acting on opportunity as opposed to planning – I would consider that escalation. However, he’s not grabbing women off the street willy-nilly, so he’s still controlled and we have to assume he functions quite normally – even when he has his victim in situ.’

‘Does he live in the region he’s abducting them from?’ Tom asked. ‘Or closer to Glendalough where he buries them?’

Linda frowned.

‘Hmm. Now there’s a question. It’s more likely that the Munster region is his hunting ground and he buries them close to where he lives so he can keep an eye on them, visit them, that sort of thing. So you’re looking at Dublin and its surrounding counties for his home – Wicklow, Kildare. I’d pay special attention to Meath, where Fiona lived. It would fit with the escalation theory that he would take somebody from near his home, possibly somebody he’s known for a long time. He might be a man who travels a lot and especially to the south – a sales rep, something like that. Most serial killers are occupationally mobile. It’s entirely in keeping with the facts that he would kidnap and kill in one place and dispose of his victims in another.’

She turned and wrote: Geographically mobile.

‘Why does he do it?’ This was Ray. He’d crossed over to where Tom was sitting and reclaimed his half-empty bottle of water, throwing his boss a dirty look.