Ricky decided it would be an easy shake-down. He threatened to tell all to Tonin’s family. He started asking for money on the quiet. Never calling it a blackmail, just a bit of help to get him through hard times. But he didn’t go away. He kept coming back for more.

Ricky’s train that night had been almost an hour late. And I knew enough about Ferrovie dello Stato to know that a late train always gets later. If a train is an hour late now, in half an hour it will probably be two hours late. That’s the way with Ferrovie dello Stato. Ricky would have been looking around for some way to kill time. A restless type like him didn’t sit in the waiting room helping old ladies with the crossword.

So he had wandered around the station looking for something to do. By chance or design, someone saw him at the station and it went from there. Someone had seen to him. Someone decided to do them all a favour.

It was pretty vague, but it seemed to fit the facts. Once Riccardo had disappeared Tonin kept his paternity hidden because he feared his family was involved. He had lost one son and didn’t want to lose another. He must have guessed years ago that Sandro was involved, and that to tell the world that he, Tonin, was Riccardo’s father, would lead everyone to the boy who, until then, had been his only son: Sandro.

It added up but I’m not so keen on guesses. For a ‘scomparso’ to become a ‘presunto morto’ you need more than guesses. I turned my keys and let myself into the flat. It was freezing. The boiler must have broken again.

I took an ingot of beeswax out of a cupboard. It was thick and heavy, so I shredded it with a cheese grater into a pan. I warmed it gently, adjusting the flame so that the deep yellow lump slowly melted.

The old Salati woman’s death had been a spanner in the works. She had made sure that when she died there would be one last investigation into the disappearance of her son, Ricky. Sandro had overheard about it in the office when the two receptionists had been talking about their work one Saturday morning. So Sandro decided to make the most public declaration of mourning possible and make it look like Riccardo had just been playing hide-and-seek for more than a decade. It was an amateur attempt to put us off the scent. But it was clear that old Massimo Tonin hadn’t made the payment. A lawyer knows all about the documents he leaves in his wake and wouldn’t be that inept. The only explanation was that the son was using the father’s credit card. Nothing new about that in this city.

Then Umberto found out about his late mother’s love life; he wanted it out with the Tonins. He stormed round there, to the domestic nest rather than the chilly offices of the lawyer. Salati stammered his disgust, and the Tonin woman panicked. She thought Salati knew more than he said and she called her son.

Sandro assumed his time was almost up. The only way to make sure his disposal of Ricky stayed secret was to dump Umberto. He hangs around outside the block of flats and gets impatient. He buzzes Umberto and tells him to come down, says there’s a delivery, or an emergency, anything to get the man in his sights. When Umberto goes outside Sandro’s on to him. He smacks Salati on the side of the head with anything he has to hand.

I put on another pan and heated up some oil I had bought in that African shop just off Viale Imbriani. The kitchen began to smell good, like suncream or something, and it made me feel better. It smelt like a childhood summer from long ago. I mixed the oil and the wax and stirred in a few spoonfuls of honey and some vanilla drops. The liquid was transparent but thick. I took it off the heat and poured it into tiny glass pots. I filled about sixty all told.

Sandro must have gone upstairs. He had seen Salati there with his body broken and had decided to go upstairs and open a door on to Salati’s terrace. Make it look like a suicide and whilst he’s there, check Salati hasn’t done anything foolish like write a confessional. That’s what the old woman heard in the flat below: Sandro pulling up shutters.

And then he makes his only mistake. He forgets to put Salati’s keys somewhere. He walks out with them for some reason. Maybe his mind was elsewhere, or else he thought Salati really had written it all down and that the keys would be useful. It all came back to the keys.

Whilst the mixture was cooling it turned white, and I wrote small labels that I stuck on the lids one by one. It was satisfying work, making something beautiful and useful, doing something slowly and methodically. It was the opposite of detection, the hurried discovery of something terrible, a discovery that was useless except for the purposes of punishment or revenge.

I sat down in the armchair once I was done and tried to think about nothing. It’s harder than it sounds. I tried for half an hour to think of nothing, but I kept seeing keys and Visa slips and Umberto Salati’s bushy moustache caked with dry blood.

I woke up a few hours later feeling brittle, like I could snap for lack of sleep. I looked at the clock and it was only just four in the morning. I tried to get up quietly, but every movement seemed loud and clumsy. As I walked towards the kitchen, the tendons in my left ankle clicked as I went.

The entire city was asleep. In that cold silence every thought seemed powerful and unopposed and fantasies took possession of my mind.

I sat in the armchair. I could hear traffic in the distance, hear someone’s boiler firing up.

It was surprisingly noisy once you were used to the quiet. And each sound could have been any number of things.

I was thinking about what the old Veronesi couple had heard. The cat’s bell, they said.

I couldn’t tell if it was a dream or something real that I was remembering. Time seemed to pull apart for an instant, allowing that instant to pass in slow motion, to become something more than what it was.

I stood up and went over to the phone table where I drop my keys each night. I picked them up as silently as possible, but there was still the rattle of kissing metal. They hadn’t heard the cat, I realised, but someone lifting the keys from Umberto Salati’s pocket.

I slipped the keys into my jacket and counted out the eight specimen keys from Sandro Tonin’s bag. I zipped them into my inside pocket and pulled the door shut.

The fog was thick but the green neon of a chemist’s cross was bright. As the lines came on one by one the air seemed to turn into algae.

It was still early. I had been outside Sandro Tonin’s flat since before five and there had been no movement. I was yawning every few minutes and wondering whether I should go back to bed.

At a few minutes past eight Sandro came out dressed for work. He was headed for the office by the look of his pressed trousers. I could hear the sound of his heels clicking as he walked.

Once he was out of sight I walked up to Sandro’s block and quickly tried one key after another. The gate gave way. I did the same for the door on the inner courtyard and got into the building.

Inside I slipped the keys back into my pocket and started walking up the stairs. A young boy was heading out in running gear and I stopped him.

‘You know which floor Sandro Tonin is on?’

‘Third,’ the boy said enthusiastically.

He ran off and I went up another two floors.

There were two doors on that floor. I tried the one to the right because there was an umbrella bucket outside the door with an expensive walnut wood handle poking out. That would be Sandro, I thought.

I rang the bell expecting nothing but I heard the sound of someone inside and eventually the door opened.

It was a girl. Her face was on and she had a cup of coffee in her hand.