It’s obvious that he has nothing to tell me. That’s why there’s been a two-course delay. Now he wants to use the paramedics as an excuse not to carry on with the briefing.

‘I’m happy,’ I tell him. ‘I don’t see a problem.’

There is a large, visible intake of breath. Leaning over, Bonilla lifts a battered briefcase from the ground and extracts a worryingly slim file. The sunglasses come off, a pen appears from his jacket pocket and he rolls up the sleeves of his jacket like Tubbs in Miami Vice.

‘Rosalía Dieste… Rosalía Dieste.’

‘Yes.’

‘Well, we must confess that she was not an easy assignment for us. Not easy at all.’

So effortless the slip into the plural; collective rather than personal responsibility.

‘I see.’

‘We were constricted by not knowing the exact nature of your enquiry.’

‘I don’t understand. I explained to Mar -’

‘Yes of course you did, of course you did.’ A pause. ‘But the exact nature.’

A teenage girl strolls past the restaurant and, like a tracking shot, Bonilla scopes her nodding breasts all the way to the edge of the lake.

‘Eduardo?’

‘Sí?’

‘I explained to Mar what I wanted. Deep background. Previous relationships. Some information about Plettix and Gael. I thought I made it clear.’

Thick lips bulge in thought. There is a moment of reflection before some of the poise and self-assurance returns to his face. He taps the file, mutters the word ‘Gael’ and begins searching for a piece of paper. There cannot be more than twenty pages contained within the folder’s narrow cardboard flaps, but it is some time before he has found it.

‘Gael and Rosalía met on holiday two years ago,’ he announces finally. ‘At the Parador in Cáceres.’ The waiter comes back and takes an order for coffee. I ask for a cigar to buy more time. ‘He was away on a business trip to Lyons this weekend.’

‘I knew that. What’s his job?’

‘Gael Marchena works for a small French pharmaceutical company called Marionne. The headquarters are based near Tours. He trained as a chemist at a university in Paris and was recruited after graduation.’

‘He’s French?’

Bonilla has to look that one up.

‘Spanish.’

One of the paramedics looks over and I wonder if I have underestimated the surveillance threat. Bonilla scratches his neck.

‘Rosalía and Gael have lived together at an apartment in Calle de Jiloca for under one year now’ He is still reading from the file. ‘The rent is shared, they pay by a regular monthly transferencia from Gael’s account with the BBVA. He is under a lot of pressure from his family to be married.’

A strangled laugh.

‘You listen to his telephone conversations?’

‘I cannot necessarily reveal the source of my information.’ This appears to be a small moment of triumph for Bonilla and he celebrates by putting his sunglasses back on. ‘I have a telephone record of all calls made from Señorita Dieste’s landline at Calle Jiloca.’ He passes a Telefónica bill across the table. The paramedics are making a lot of noise, laughing and joking and raising glasses over the table. ‘If you were concerned about an infidelity, Señor Thompson, my experience tells me people are using a secret mobile telephone that their partner knows nothing about. We have only been able to trace one mobile belonging to Rosalía, and the results were completely normal.’

‘Just calls to friends, calls to Plettix?’

‘Exactly.’

‘And email?’

‘Nothing.’

‘No strange internet activity? No private accounts with Yahoo, Hotmail, Wanadoo?’

He shakes his head. An insect lands on my arm and I flick it away.

‘No.’

‘And what about her past? Her education, previous relationships?’

The coffee comes, with a tubed Romeo y Julieta cigar proffered on a small white plate. It may be simply my characteristic paranoia, but I have a developing sense of anxiety that Bonilla is about to mention Mikel by name. Either that, or his whole approach is a charade designed to lure me into confession. If he reads the papers or watches the television news, he will know about Arenaza’s disappearance. Any evidential link with Rosalía and there’s a significant chance that he will have already alerted the police.

‘Again you asked us to look into this for you and we discovered nothing of consequence. Miss Dieste had a boyfriend for three years at the Universidad Politécnica de Madrid…’

‘…Called?’

Bonilla checks his notes.

‘Javier Arjona. But he moved to the US in 1999.’

‘And no pseudonyms?’

‘No pseudonyms.’

‘Dieste took one year in the United States at the University of Illinois. After that, she returned to Madrid, completed her degree and went directly to France to complete postgraduate study in energía nuclear.’

‘Nuclear energy? Where?’

‘The tesis was at the INSTN. That lasted for two years. Then more post-doctorate work at the Argonne Laboratoire Nationale. I have to say that my impression of her is as a very focused, very hard-working and ambitious person, what we sometimes call in Spanish una empollona.’

It’s a word I have not heard before which Bonilla loosely translates as a ‘geek’. Three South American musicians hove into view and start to set up operations about ten feet away from our table. The tallest of them, a battered-looking accordion slung over his embroidered white shirt, steps forward to greet the assembled diners with an accent that sounds Peruvian. Across the restaurant, a lone balding businessman looks down into his plate and groans. He knows what’s coming. Now the drum machine starts up, attached to a powerful, battery-powered amplifier, and before long we are treated to the first bars of ‘My Way’ played at astonishing volume.

‘Oh Christ.’

‘You don’t like this music?’ Bonilla is grinning.

‘I was just enjoying the peace and quiet.’ I drop the head of the cigar onto the ground and light the end very slowly. ‘What else have you found out? Nothing from the weekend? Just this Bunny Girl party? Just brunch at Delic?’

‘I am afraid so, Señor Thompson. I am afraid so. Why you want to know about her? What is your interest?’

I have to give him something. It’s becoming a problem.

‘She may have been having an affair behind Gael’s back. With the husband of a friend of mine. It’s a delicate situation.’

‘Really? Who? What was his name?’

Bonilla seems excited.

‘I would rather not say. He’s from a well-known family in Spain and he doesn’t want any scandal.’

‘So it is the husband who hired you?’

‘That’s right.’

Bonilla is bound to see through this, but it’s the best I’ve got. ‘He wants to know how serious she is. Whether she intends to leave Gael or if she’s just after his money.’

‘He is rich, your friend?’

‘Very.’

‘I see. And where does he live?’

‘In the Basque country.’

Bonilla almost splits his jacket. ‘In the Basque country? Joder.’

‘You look shocked.’

‘No. It’s just not something we were able to discover. Mar I think checked all the numbers for source and not one of them originated in San Sebastián.’

I feel an awful lurch of shock, oddly close to betrayal. Bonilla has slipped up. He knows something.

‘Why did you say San Sebastián? How do you know where my friend lives?’

He looks baffled.

‘I didn’t. Is that his home?’ A consummate impression of innocence registers across his face; no blushing, no tell-tale covering of the nose or mouth. A man suspected of lying who has done no wrong. ‘I just mention it by coincidence. It’s the city I associate with the Basque country. I have been there and I do not like Bilbao. Too much industry. San Sebastián is beautiful, no?’

For a moment I do not know whether to carry on. I should have gone to the police weeks ago and saved myself all this trouble and money. If Arenaza is dead and Bonilla knows about his relationship with Rosalía, I could be accused of conspiring to pervert the course of justice. But if the slip really was just coincidence, I have €1,600 riding on the rest of this conversation.