Small things set the fear off. Simple things like Harold pausing suddenly in the flow of conversation, listening and alert. Something about his sudden tensing makes me stop too, my mind leaping with possibilities.

The sounds around us are mixed. A thin note of birdsong from the Flagstaff Gardens. The hum of traffic on surrounding streets. A tiny crack of noise, like a stick breaking underfoot. And in the distance the sound of running rises up clearly for a moment and fades. Small inconsequential sounds that are carried on the still air and give no clue as to the reason for Harold's sudden pause.

In the park, lights shine palely along meandering pathways and I catch a momentary glimpse of the runner on the winding, middle footpath. A dark-clothed figure against a paler darkness. Despite their speed, there is an impression of awkwardness, a heaviness to one side, as though they are weighed down. And then they are gone, swallowed up by a distant plantation of tees.

'Marlo!' Harold has moved and stands some distance off, an amorphous shape in the gloom. A shape I distinguish into separate components as I cross the icy grass towards him. Part Harold, part park bench and something else. Someone else. Someone who lies awkwardiy, body slumped, head twisted against the metal rail. The air is cold but my skin is suddenly clammy, sweat prickling under my arms.

'Call an ambulance, Mario. It's Bill. The old man... I heard him call out just now. I don't know.. .' He trails off.

Bill's body is engulfed in shadows but his face shows clearly in the park light and I see the trail of blood on his face, the stain of it in the stubble of his beard and on the grass beneath him. His eyes are open but only one is visible, pale and staring.

I fumble in my bag for my mobile phone, with hands that are uncharacteristically sluggish. The call made, I turn back to Harold. 'They're on their way. How is he?'

Harold shakes his head. 'I don't know. He spoke to me just now, but... I can't feel a pulse.' I put my hands on Harold's shoulders to reassure him and feel, not the familiar bulky overcoat that I expect but a layer of polyester that I recognise as one of his waistcoats. He has covered Bill with his coat and taken his hand, offering up his own warmth. He must be freezing.

How long we stand there linked in this strange tableau of stillness, I don't know The air is sharp with cold and mist and Bill Diamond lies as still as death. Around us, no voices break the silence, no movement erodes the sense of isolation. Save for the hum of cars around the park and the restless glitter of their lights, it feels as though we are only people on the planet. When the sirens sound in the distance, they seem plaintive and disembodied.

'I'll go and meet them Harold, bring them over.'

He shifts and stands up. 'Yes.'

Above me, his face is pale and expressionless, but I can tell by the downward slump of his shoulders that he has given up hope.

*****

Torches and a brisk efficiency. We stand out of the way and watch the flurry of activity give way almost immediately to something more orderly and routine. There is no need for haste. Harold was right but I had known it too, felt it in the set of Harold's shoulders and the absolute stillness of death.

The police arrive next. More activity and voices. Next to me Harold is unmoving and unspeaking. When I put my hand on his arm, I feel his coldness with a little jolt of shock. The practical part of my brain kicks in and I remember that Harold keeps a spare jacket at work, and work is just across the road. There is nothing more I can do here anyway.

After the stillness of the park, my footsteps are loud on the wooden staircase leading up from the street. Inside, the office is warmer than I expected and there is a faint spring-like scent that surprises me. I don't switch the lights on as I don't intend to stay long and there should be enough light from William Street to see by. This is a mistake, though, because I collide heavily with Irene's chair, for once, not pushed in with its usual precision. Irene's desk is office legend. She always tidies it before leaving - documents filed, desk calender turned, diary closed, computer, phone and in-trays always in precise, unchanging positions. I'm surprised to see that the phone has shifted marginally too.

As I collect Harold's jacket from behind his door, the sudden brilliance of police lighting draws me to the window A uniformed officer keeps spectators to the footpath but, away from the bright lights, a figure moves along the middle footpath, heading towards the station, the opposite way to the runner earlier. There is nothing fleet about the man I watch now. A squat figure, slow and plodding, bowed down with heavy clothing. He is the only person who seems to be unaware of the activity going on around him.

Harold is with a police officer on the footpath, standing in the hazy glow of a streetlight that shows his height and bulk and close-cropped silver hair. I hurry back out with his coat, and he pauses in mid-sentence to slip it on, not really registering.

'I heard him call out...'

'Leave it for now,' the officer says, kindly enough. 'You can tell us at the station.'

After the chill of the park, the Police Centre in Flinders Street, is infinitely warm and inviting. I have been involved once before in a police investigation and give myself up to the procedures of it. I give my statement to a uniformed officer, going over what I saw, what I heard and what I knew of the dead man, but none of it amounts to much. I had never actually met Bill Diamond but Harold had told me about their recent conversations and I had seen them from my office window occasionally, sitting together in the park on sunny days. Bill was an old man with an air of watchfulness that showed in the constant moving of his head. But that is all I know of him - just a few impressions. It is my mention of the runner that arouses most interest.

'Can you describe them?'

I think back, remembering the speed and the awkwardness of that dark blur of clothing, but can recall nothing more.

'Anyone else you saw in the park?'

I tell her of the later sighting. The slow man with the heavy clothing, moving towards the station. But this was a comparatively long time after the death.

Next she asks for details of our work routine. We usually finish at half past five, but tonight we were held up by a missing document and a couple of last-minute phone calls. Harold had waited on the street for the courier and I had handled the phone calls, impatient with the delay, especially as I had to consult documents and files that had afready been consulted many times before.

The officer has no more questions for me and I wait for Harold, drinking tea that I don't want, holding the cup for warmth, and aware of a vague hunger that has as much to do with cold and nerves as lack of food. As I sit there my thoughts go more to Harold than to the dead man. It is Harold who spent his lunch hours with him, who heard him cry out tonight and held his hand while life slipped through his fingers. I wonder how Harold is coping.

Eventually he comes out and I see with some surprise that his clothes are different. The jacket is the same but the trousers are not the usual luxurious fabric or stylish cut that I associate with Harold. What worries me most is the paleness of his face and the bruised look to the skin under his eyes. For the first time since I have known him, he looks his age.