The elder of the two men took her gently by the arm and walked her through to her kitchen where he helped her into a chair at the scrubbed pine table. The younger man put the kettle on, knowing this was a cup of tea and a chat scenario; the poor woman looked mortified.

‘I’m sorry to be the harbinger of such distressing news, but we feel we have to warn you. Your son has murdered a man called Dougie McManus, and we believe he may come here at some point. In the squat where he was living we found exercise books that were your son’s, in which he detailed how he was going to harm you. Burn you out, in fact. So we need you to be on your guard.’

Cynthia nodded, but her mind was whirling. ‘He’s killed someone. He has finally killed someone.’

The policeman looked at his young counterpart to see how he was getting on with the pot of tea.

‘I’m afraid that’s true, Mrs Tailor—’

She interrupted him. ‘I’m Callahan – Miss Callahan. I reverted to my maiden name after my husband’s death.’

He made a note of that in his little book. ‘Now, has he approached you?’

She shook her head. ‘No, but I think he’s been stalking me for a while. My daughter warned me about him the other day, funnily enough. You know he has severe mental problems?’

The policeman said he did.

‘He was diagnosed schizophrenic at a very young age, after his father committed suicide. It’s very sad. I need to know, have you any idea where he could be?’

‘Well, Miss Callahan, I was going to ask you that very same thing.’

She shook her head again. ‘I avoid him like the plague, to be honest. He’s a very difficult person to deal with. He believes he is being watched by government forces. If you talk to his doctors they will explain it to you.’

He nodded – he had spoken to the doctors already.

‘My daughter might know something, but I doubt it – same with my parents. He’s not someone you encourage into your life, if you get my drift. Very violent, and very easily riled up. He cut a neighbour’s cat’s throat when he was just coming up to nine.’

The policemen were surprised to note that, as she described her son’s problems, there was no real emotion there at all for him.

‘My daughter seemed to think he was on drugs. She said he looked like he was on something when she saw him just down the road from my house. She stopped the car and spoke with him. I had her little daughter staying with me at the time so naturally she was worried in case he came here in front of the child . . .’