Then, seeing the effect of these words: ‘You’re in keech up to your chin, son. Start at the beginning and leave nothing out.’

Corbie sang like his namesake: it didn’t make for edifying listening, but it had an honest sound. First, though, he asked for some paracetamol.

‘I’ve got a hell of a headache.’

‘That’s what daytime drinking does to you,’ said Rebus, knowing it wasn’t the drinking that was to blame – it was the stopping. The tablets were brought and swallowed, washed down with water. Corbie coughed a little, then lit another cigarette. Rebus had stubbed his out. He just couldn’t deal with them any more.

‘The car was in the lay-by,’ Corbie began. ‘It was there for hours, so I went and took a look. The keys were still in the ignition. I started her up and brought her back to the farm.’

‘Why?’

He shrugged. ‘Never refuse a gift horse.’ He grinned. ‘Or gift horse-power, eh?’ The two detectives were not impressed. ‘No, well, it was, you know, like with treasure. Finders keepers.’

‘You didn’t think the owner was coming back?’

He shrugged again. ‘Never really thought about it. All I knew was that there were going to be some gey jealous looks if I turned up in town driving a BMW.’

‘You planned to race it?’ The question came from DS Knox.

‘Sure.’

Knox explained to Rebus. ‘They take cars out on to the back roads and race them one against one.’

Rebus remembered the phrase Moffat had used: boy racer. ‘You didn’t see the owner then?’ he asked.

Corbie shrugged.

‘What does that mean?’

‘It means maybe. There was another car in the lay-by. Looked like a couple were in it, having an argument. I heard them from the yard.’

‘What did you see?’

‘Just that the BMW was parked, and this other car was in front of it.’

‘You didn’t get a look at the other car?’

‘No. But I could hear the shouting, sounded like a man and a woman.’

‘What were they arguing about?’

‘No idea.’

‘No?’

Corbie shook his head firmly.

‘Okay,’ said Rebus, ‘and this was on . . .?’

‘Wednesday. Wednesday morning. Maybe around lunch-time.’

Rebus nodded thoughtfully. Alibis would need re-checking . . . ‘Where was your mother all this time?’

‘In the kitchen, same as always.’

‘Did you mention the argument to her?’

Corbie shook his head. ‘No point.’

Rebus nodded again. Wednesday morning: Elizabeth Jack was killed that day. An argument in a lay-by . . .

‘You’re sure it was an argument?’

‘I’ve been in enough in my time, it was an argument all right. The woman was screeching.’

‘Anything else, Alec?’

Corbie seemed to relax at the use of his first name. Maybe he wouldn’t be in trouble after all, so long as he told them . . .

‘Well, the other car disappeared, but the BMW was still there. Couldn’t tell if there was anyone in it, windows being tinted. But a radio was playing. Then in the afternoon –’