'Any idea who did it?'

Dicky gave a tiny derisive hoot. 'Are you joking? The report says the bullets hit the bathroom wall with abnormally low velocity. The ballistics boys say the bullets had been specially prepared by experts – they'd had a proportion of their powder removed. Well, that sounds like a laboratory job, eh? That's our KGB friends, I think. Why do they do that, Bernie?'

'So they don't go through the next two or three houses and spoil the neighbours' television. Who found him?'

'His sister. She let herself in with her own key. She'd come to see if he was okay after that business with the sleeping pills. If it hadn't been for that, we wouldn't have discovered the body until tomorrow morning. I'd always suspected that Trent was queer, didn't you? I mean, him never being married. But giving the sister a key to the house makes that unlikely, wouldn't you say?'

'Anything else, Dicky?'

'What? No. But I thought I should ask you if he was acting normally when he left you this morning.'

'I can't help you, Dicky,' I said.

'Well, I know you've got an early start in the morning. Frank says wrap up well. It's cold in Berlin.'

After I rang off, I returned to my desk. When I unwrapped the pistol, I found a series of holes in the woollen scarf. Rolf Mauser had wrapped the gun in it before shooting Trent. A revolver can't be silenced any other way. I had to use a magnifying glass for a clear sight of the marks left on the bullet cases by the process of hand-loading. There was no doubt that the bullets had been specially prepared by someone with gunsmith's tools and powder measure.

I sat down and looked at the TV before switching off. The steamer was sinking; the men were drowning. I suppose it was some kind of comedy.

21

It was very very dark and Frank Harrington was being ultra cautious, using the electric lamp only to show me a safety well into which I might fall, or large puddles, or the rails when we had to get across to the other side of the railway track.

There is a curious smell in Berlin 's underground railway system. It brings to mind the stories about engineers blasting the locks of the canal between Schöneberger and Möckern bridges in those final hours of the war, so that the tunnels flooded to drown civilians, German soldiers and Russians alike. Some say there was no flooding – just leaks and water that came through the damaged bulkhead that guards the Friedrichstrasse U-Bahn station from the cold waters of the Spree. But don't deny those nightmares to anyone who has picked his way over the cross-ties in the darkness after the trains have stopped, for he will tell you about the ghosts down there. And the curious smell remains.

Frank moved forward very slowly, talking softly all the while so that I would know where he was. 'Half the passengers on the underground trains going from Moritzplatz to Voltastrasse don't even realize that they actually go under East Berlin and back into the West again.'

'Are we under the East Sector yet?' I asked.

'On this section of line, they do know of course. The trains stop at Friedrichstrasse station and the passengers are checked.' He stopped and listened, but there was only the sound of dripping water and the distant hum of the electric generators. 'You'll see the marks on the tunnel wall when we get that far. There's red paint on the wall to mark the boundary.' He flashed his light on the side of the tunnel to show me where the marks would be. There was nothing there except bundles of wires sagging from support to support and blackened with decades of filth. As he switched off his lamp, Frank stumbled into a piece of broken drain and cursed. It was all right for him; he had rubber boots on, and wore old clothes under his railway-engineer's overalls. The clothes I wore under my overalls were all I had for my time in East Berlin. And we'd both decided that carrying case or a parcel in the small hours was asking to be stopped and searched.

We walked slowly along the track for what seemed like hours. Sometimes Frank stopped to listen, but there was only the sudden scratching sounds of rats and the ceaseless hum of electricity.

'We'll wait here for a bit,' said Frank. He held his wristwatch close to his face. 'Some nights there are East Berlin railway engineers going down the track to check the apparatus at the terminal – what used to be Kaiserhof station. Thälmannplatz, they call it nowadays. The Communists like to name the streets and stations after heroes, don't they?' Frank switched on his lamp long enough ta show a recessed space in the wall of the tunnel, containing a yellow-painted metal box with a telephone in it. This was one of the places the drivers had to come to if their train stopped between stations. There was a bench there too, and Frank sat down. We were not far below street level and I could feel a cold draft coming down the air shaft.

'Ever wonder why the Berlin Wall follows that absurd line?' said Frank. 'It was decided at a conference at Lancaster House in London while the war was still being fought. They were dividing the city up the way the Allied armies would share it once they got here. Clerks were sent out hotfoot for a map of Berlin but the only thing Whitehall could provide was a 1928 city directory, so they had to use that. They drew their lines along the administrative borough boundaries as they were in 1928. It was only for the purposes of that temporary wartime agreement, so it didn't seem to matter too much where it cut through gas pipes, sewers and S-Bahn or these underground trains either. That was in 1944. Now we're still stuck with it.' We were sitting in the dark. I knew Frank was dying for a puff at that damned pipe, but he didn't succumb to the temptation. He talked instead.

Frank said, 'Years back, when the Communists started building that incredible great satellite city at Marzahn, they wanted it to have its own administration and become a Stadtbezirk, a city borough in its own right. But the Communist lawyers sat down with the men from Moscow and went through those old wartime agreements. The outcome was that they were told on no account to create a new Bezirk. By breaking the old agreement, they would open the way for the Western Powers to make changes too.'

'Lawyers run the world,' I said.

'I'm going to let you out into the street at Stadtmitte station,' Frank said. He'd told me all about it, shown me a map and photos, but I didn't interrupt him when he told me everything all over again. 'Stadtmitte is an intersection. East German trains and West German trains both pass through. On different levels, of course.'

'How long now, Frank?'

'Relax. We must wait until we're sure the East Germans are not repairing their track. They're not armed but they sometimes have radios to talk to the men who switch off the juice. They have to be sure the lengthmen won't be electrocuted when they start work.'

We waited in the darkness for what seemed an age. Then we walked slowly along the tunnel again. 'In 1945, the Red Army – fighting their way into the city – were held up at Stadtmitte U-Bahn station,' said Frank. 'The station was being used as headquarters by the SS Division Nordland. They were the last German regulars holding out, and they weren't very German. Nordland had become a collection of foreign volunteers, including three hundred Frenchmen who'd been sent from another unit. The Germans were shooting from about where we are standing now and the Russians couldn't get down onto the track. You know that old saying about one man can hold off an army if he fights his battle in a tunnel. Well, the Germans were fighting their final battle and it was in a tunnel.'

'What happened?'

'The Russians manhandled a field-artillery piece down the entrance steps, along the platform, and onto the tracks. Then they fired along the tunnel here, and that was the end of the story.' Frank stopped suddenly and held his hand outstretched as a warning to be silent.