Bromley took the stem of the pipe from his mouth and ran his left hand through his short-cropped beard. ‘Mr Nguyen, you must realise that we are doing everything we can to find the people who killed your wife and daughter. Everything that can be done, is being done, you must believe me when I tell you that. There is no point in you coming here every day. If there is something to tell you, we will telephone you or we will write to you. Do you understand?’

The old man nodded twice, and his smile widened. Several of his back teeth were missing, and one of his canines was badly chipped. ‘I understand, Detective Chief Inspector Bromley,’ he said slowly.

Bromley continued with the speech he’d rehearsed in his mind while travelling down in the lift. ‘The men are members of the IRA, we think they are living in London, probably moving from place to place, perhaps living in bedsitters or cheap boarding houses. They will be using false names and they will be experts at blending into the background. What I am trying to say to you, Mr Nguyen, is that it will be very difficult to find them. Do you understand?’

Nguyen nodded again.

‘In fact, it might well be that we never find them. That is a possibility that you must come to terms with. Sometimes the IRA will mount a bombing campaign and then the political climate changes and the bombing stops. If that were to happen, we might never catch the men. But at least the killing will stop. Do you understand?’

Nguyen nodded. ‘No,’ he said quietly. ‘That cannot be so.’

‘It is so,’ said Bromley.

‘It is not something I can accept, Detective Chief Inspector Bromley,’ the old man said, still smiling as if he was afraid to offend the policeman. ‘You must catch these men.’

‘If it is possible, we will, Mr Nguyen. That I can promise. But if it is impossible . . .’ He shrugged and put his pipe back into his mouth.

‘These men in London. They are doing this because they are told to, yes?’

‘We believe they are members of the IRA, yes.’

‘But this IRA is not a secret organisation. You know who is in it, you know where they are.’

‘Yes,’ said Bromley doubtfully, not sure where the man was heading.

‘Then why cannot you arrest someone else who you know is in the IRA and make them tell you who is doing the killing?’

Bromley smiled ruefully, knowing that there were a good many men in the Royal Ulster Constabulary and even his own squad who would be more than happy to do just that, to pick them up off the streets and take them to an underground cell and attach electrodes to their private parts and squeeze every bit of information out of them. And there were others who’d welcome a shoot-to-kill policy, official or unofficial, so that they could blow them away without bothering about the niceties of evidence and procedure and witnesses.