Hogan, standing by the railings, had seen Rebus's attempts at communication.

`Someone you know?’

'Kirstin Mede.’

Hogan placed the name. `The one who did those translations?’

Rebus looked up at the Slavic Studies building. `Have you tracked down David Levy?’

`Daughter still hasn't heard from him.’

`How long has that been?’

`Long enough to seem suspicious in itself, only she doesn't seem too bothered.’

`How do you want to play this?’

Rebus asked.

`Depends what he's like.’

`You ask your questions. Me, I just want to be there.’

Hogan looked at him, then shrugged and pushed open the door. They started to climb the worn stone steps. `Hope they haven't put him in the penthouse.’

Colquhoun's name was on a piece of card stuck to a door on the second floor. They pushed it open, and were confronted with a short hallway and another five or six doors. Colquhoun's office was first on the right, and he was already standing in the doorway.

`Thought I heard you. Sound carries in this place. Come in, come in.’

He wasn't expecting Hogan to have company. His words dried up when he saw Rebus. He walked back into his office, motioned for both officers to sit, then fussed about moving their chairs around so they'd be facing his desk.

`Terrible muddle,' he said, kicking over a pile of books.

`Know the feeling, sir,' Hogan said.

Colquhoun peered in Rebus's direction. `My secretary says you used the library.’

`Filling in some of the gaps, sir.’

Rebus kept his voice level.

`Yes, Candice…’

Colquhoun was thoughtful. `Is she…? I mean, did she…?’

`But today, sir,' Hogan interrupted, `we want to talk to you about Joseph Lintz.’

Colquhoun sat down heavily in his wooden chair, which creaked under the weight. Then he sprang to his feet again. `Tea, coffee? You must excuse the mess. Not normally this disorganised…’

`Not for us, sir,' Hogan said. `If you'd just take a seat?’

`Of course, of course.’

Again, Colquhoun collapsed on to his chair.

`Joseph Lintz, sir,' Hogan prompted.

`Terrible tragedy… terrible. They think it's murder, you know.’

`Yes, sir, we do know.’

`Of course you do. Apologies.’

The desk in front of Colquhoun was venerable and spotted with woodworm. The shelves were bowed under the weight of textbooks. There were old framed prints on the walls, and a blackboard with the single word CHARACTER on it. University paperwork was piled on the window ledge, all but blacking out the bottom two panes. The smell in the room was that of intellect gone awry.

`It's just that Mr Lintz had your name in his address book, sir,' Hogan continued. `And we're talking to all his friends.’

`Friends?’

Colquhoun looked up. `I wouldn't call us "friends" exactly. We were colleagues, but I don't think I met him socially more than three or four times in twenty-odd years.’

`Funny, he seems to have taken an interest in you, sir.’

Hogan flipped open his notebook. `Starting with your address in Warrender Park Terrace.’

`I haven't lived there since the seventies.’

`He also has your telephone number there. After that, it's Currie.’

`I thought I was ready for the rural life…’

`In Currie?’

Hogan sounded sceptical.

Colquhoun tipped his head. `I eventually realised my mistake.’

`And moved to Duddingston.’

`Not at first. I rented a few properties while I was looking for a place to buy.’

`Mr Lintz has your telephone number in Currie, but not for the Duddingston address.’

`Interesting. I went ex-directory when I moved.’

`Any reason for that, sir?’

Colquhoun swayed in his chair. `Well, I'm sure it sounds awful…’

`Try us.’

`I didn't want students bothering me.’

`Did they do that?’

`Oh, yes, phoning to ask questions, advice. Worried about exams or wanting deadlines extended.’

`Do you remember giving Mr Lintz your address, sir?’

`No, I don't.’

`You're sure of that?’

`Yes, but it wouldn't have been hard for him to find out. I mean, he could just have asked one of the secretaries.’

Colquhoun was beginning to look more agitated than ever. The little chair could barely contain him.

`Sir,' Hogan said, `is there anything you want to tell us about Mr Lintz, anything at all?’

Colquhoun just shook his head, staring at the surface of his desk.

Rebus decided to use their joker. `Mr Lintz made a phone call to this office. He was talking for over twenty minutes.’

`That's… simply not true.’

Colquhoun mopped his face with a handkerchief. `Look, gentlemen, I'd like to help, but the fact is, I barely knew Joseph Lintz.’

`And he didn't phone you?’

`No.’

`And you've no idea why he'd keep note of your Edinburgh addresses for the past three decades?’

`No.’

Hogan sighed theatrically. `Then we're wasting your time and ours.’

He got to his feet. `Thank you, Dr Colquhoun.’

The look of relief on the old academic's face told both detectives all they needed to know.

They said nothing as they walked back downstairs – like Colquhoun had said, sound could travel. Hogan's car was nearest. They rested against it as they talked.

`He was worried,' Rebus said.

`Hiding something. Think we should go back up?’

Rebus shook his head. `Let him sweat for a day or so, then hit him.’

`He didn't like the fact you were there.’

`I noticed.’

`That restaurant… Lintz dining with an elderly gent.’

`We could tell him we've got a description from the restaurant staff.’

`Without going into specifics?’

Rebus nodded. `See if it flushes him out.’

`What about the other person Lintz took to lunch, the young woman?’

`No idea.’

`Posh restaurant, old man, young woman…’

`A call girl?’

Hogan smiled. `Do they still call them that?’

Rebus was thoughtful. `It might explain the phone call to Telford. Only I doubt Telford's daft enough to discuss business like that from his office. Besides, his escort agency runs from another address.’

`Fact is, he called Telford's office.’

`And nobody's owned up to talking to him.’

`Escort agency stuff, could be very innocent. He doesn't want to eat alone, hires some company. Afterwards, a peck on the cheek and separate taxis.’

Hogan exhaled. `This one's running in circles.’

`I know the feeling, Bobby.’

They looked up at the second-floor windows. Saw Colquhoun staring down, handkerchief to his face.

`Let's leave him to it,' Hogan said, unlocking his car.

`I've been meaning to ask: how did you get on with Abernethy?’

`He didn't give me too much trouble.’

Hogan avoided Rebus's eyes.

`So he's gone?’

Hogan had disappeared into the driver's seat. `He's gone. See you, John.’

Leaving Rebus on the pavement, a frown on his face. He waited till Hogan's car had turned the corner, then went back into the stairwell and climbed the steps again.

Colquhoun's office door was open, the old man fidgeting behind his desk. Rebus sat down opposite him, said nothing.

`I've been ill,' Colquhoun said.

`You've been hiding.’

Colquhoun started shaking his head. `You told them where to find Candice.’

Head still shaking. `Then you got worried, so they hid you away, maybe in a room at, the casino.’

Rebus paused. `How am I doing?’

`I've no comment to make,' Colquhoun snapped.

`What if I just keep talking then?’

`I want you to leave now. If you don't go, I'll have to call my lawyer.’

`Name of Charles Groal?’ Rebus smiled. `They might have spent the last few days tutoring you, but they can't change what you've done.’

Rebus stood up. `You sent Candice back to them. You did that.’

He leaned down over the desk. `You knew all along who she was, didn't you? That's why you were so nervous. How come you knew who she was, Dr Colquhoun? How come you're so chummy with a turd like Tommy Telford?’