A click was instantly followed by an ammunition clip springing out of the base of the pistol grip. The officer pulled back the slide and looked into the weapon.

‘Nothing in the gun, sir. It’s empty. However, there is at least one cartridge in the clip.’

He gently placed the gun down on the material which was spread on the bonnet of McAllister’s car. He then proceeded to extract six cartridges from their holder.

‘All apparently live, sir.’

‘Right. You two get that lot to Glasgow, now. I want ballistics tests. If there were bullets found at the scene of Friday’s shooting, carry out a comparison. If none were found, take the bloody place apart until you get them. I also want a comparison with the bullets from the Boyle murder.’

The two officers glanced at each other incredulously.

‘Just do it! I don’t give a damn if you and ballistics are up all night. I want a report on my desk first thing in the morning.’

‘Boss, the Boyle bullets are productions in court. We can’t get them till tomorrow morning at the very earliest. Even then, surely we’ll need to get permission from someone? We may not be able to get our hands on them till the trial is over.’

McAllister reflected for a moment.

‘Leave that to me. Get on with what we do have. I’m going to have a few words with our Mr McGarry. I still want a report first thing tomorrow morning.’

McAllister strode to the police van which was being guarded by two uniformed officers. Perhaps he was getting somewhere – at long last. At least he was in a position to make the man think. A man who thinks is a man who worries. A man who is worried is a man who might just be inclined to talk.

‘He inside?’

‘Sir. Handcuffed to two cops as per your orders.’

‘They are not cops. They, like you, are police officers. Now, get your notebooks out, come with me and write down everything you hear – and you better hear everything.’

With that, he climbed into the back of the vehicle and sat down opposite the dejected figure. McGarry stared at the floor.

‘Thomas McGarry, I am releasing you from detention…’

The eyes came up, slowly. The look, a bizarre mixture of suspicion, controlled elation and pure hatred. Even McAllister had never experienced anything quite like it. He had confronted people who had carried out the most horrific acts. Deeds involving the kind of violence which would shock even devotees of the sickest of video nasties. Some could be described as mad. Some were quite simply bad. Some demonstrated not so much as a vestige of remorse as if what they had done was all in a day’s work. Never before had he felt himself to be in the presence of genuine evil. The eyes burned into him as if seeking to inflict harm. He shivered involuntarily.