‘Well, Bob, having a good week?’ The big man’s voice was heavy with sarcasm.

Skinner was needled into responding in kind. ‘I didn’t think you could find your way into a police office any more. What can I do for you?’

Fulton’s tone softened. ‘You can listen to me. I’m worried about you. Look, man, there are times when singlemindedness and dedication can be bad for you. You certainly didn’t do the Harveys a lot of good, did you?’

Skinner’s face was impassive.

‘What do you mean?’

‘You know what I mean. Andrew and Joy Harvey, the couple who were shot dead in Fife on Sunday. You had them under observation. Your people were spotted and the Harveys were popped. Fife CID are, as they say in the tabloids, baffled. But we’re not, are we?

‘Bob, when I asked you to drop it, I had my reasons. You ignored me. Now two more people are dead. I’m asking you again. Let it go. Please.’

Skinner looked the man in the eye. ‘You know a hell of a lot about this case, don’t you? The name Fuzzy doesn’t mean anything to you by any chance?’ Fulton looked puzzled, until he added, ‘I’ll bet that Fazal Mahmoud strikes a chord, though.’

Colour flooded into the other man’s face.

Skinner continued: ‘Is this guy radio-active or something? I have reason to believe that he might be responsible for eight murders, and you tell me to lay off him. I don’t believe what I’m hearing.’

Fulton’s voice was soft. ‘Fazal Mahmoud didn’t kill anyone, Bob, until your people in Fife got too close.’

Skinner walked around his desk to stand in Fulton’s face, setting him on his heels with the power in his eyes and the anger in his voice. ‘Are you telling me you know who did kill those people?’

‘No, man, I’m not saying that.’

‘Well, Hughie boy, you seem to know everything else. If you don’t know who, you know why. And you know why Fuzzy’s running around out there, ready to kill to avoid being traced. Give me a reason why I shouldn’t hold you here until you tell me.’

Fulton laughed. ‘Don’t be daft. You can’t touch me. All the same, I will give you a reason. Fife CID have five sets of prints, one in the laundry room, the other four all through the house. They’re looking for three people, not one — no Bill Howey didn’t tell you that, did he — and you and I know that two of them are members of your force.

‘Of course they don’t know that. They think they’re looking for a couple who left behind a set of crumpled sheets in Room 211 of the local hotel, paid cash and checked out next morning, just before the Harveys were killed. He signed the register as Mr Robert Martin, by the way. Very inventive.

‘Your halo isn’t shiny any more, Bob. Skinner’s Rules are being bent all over the place. You’re even concealing information about a murder from a fellow officer. Give this one up before you ruin your career, and more.’

Skinner’s anger had abated, but his eyes, and his voice were still rock hard. ‘Hughie, I’m not interested in your threats, or your plots. As far as I’m concerned, you can play spy-versus-spy for the rest of your fucking life.

‘I’ll give up when you give me the man who cut off Mike Mortimer’s head — no, Hughie, don’t cringe; that’s what he did — and shoved Rachel Jameson under a train. The guy who was prepared to kill three people at random, just to put us off the trail. You may or may not know who he is, but I’m damn sure you know what he is, and where his orders come from. Give him to me!’

Desperation shone from Fulton’s eyes. And to his surprise, Skinner saw real fear there too. ‘I can’t do that Bob. There’s a big game going on here, and you can’t imagine the stakes.’

‘Then get the fuck out of my office. And don’t you ever threaten me again, Hughie. Not if you like being able to walk upright!’