explained to Werner. ‘So, for example, 11 might stand for A. Transmitting them in groups of five is just a convention.’
The radio operator, an electrical engineer named Mann, read off a set of co-ordinates, and Wagner drew a line on a map with a pencil and rule. Richter put the van in gear and set off again.
The pianist continued to broadcast, his beeps sounding loud in the van. Macke hated the man, whoever he was. ‘Bastard Communist swine,’ he said. ‘One day he’ll be in our basement, begging me to let him die so the pain will come to an end.’
Werner looked pale. He was not used to police work, Macke thought.
After a moment the young man pulled himself together. ‘The way you describe the Soviet code, it sounds as if it might not be too difficult to break,’ he said thoughtfully.
‘Correct!’ Macke was pleased that Werner caught on so fast. ‘But I was simplifying. They have refinements. After encoding the message as a series of numbers, the pianist then writes a key word underneath it repeatedly – it might be Kurfurstendamm, say – and encodes that. Then he subtracts the second numbers from the first and broadcasts the result.’
‘Almost impossible to decipher if you don’t know the key word!’
‘Exactly.’
They stopped again near the burned-out Reichstag building and drew another line on the map. The two met in Friedrichshain, to the east of the city centre.
Macke told the driver to swing north-east, taking them nearer to the likely spot while giving them a third line from a different angle. ‘Experience shows that it’s best to take three bearings,’ Macke told Werner. ‘The equipment is only approximate, and the extra measurement reduces error.’
‘Do you always catch him?’ said Werner.
‘By no means. In most cases we don’t. Often we’re just not quick enough. He may change frequency halfway through, so that we lose him. Sometimes he breaks off in mid-transmission and resumes at another location. He may have lookouts who see us coming and warn him to flee.’
‘A lot of snags.’
‘But we catch them, sooner or later.’
Richter stopped the van and Mann took the third bearing. The three pencil lines on Wagner’s map met to form a small triangle near the East Station. The pianist was somewhere between the railway line and the canal.
Macke gave Richter the location and added: ‘Quick as you can.’
Werner was perspiring, Macke noticed. Perhaps it was rather hot in the van. And the young lieutenant was not accustomed to action. He was learning what life was like in the Gestapo. All the better, Macke thought.
Richter headed south on Warschauer Strasse, crossed the railway, then turned into a cheap industrial neighbourhood of warehouses, yards and small factories. There was a group of soldiers toting kitbags outside a back entrance to the station, no doubt embarking for the Eastern Front. And a fellow-countryman somewhere in this neighbourhood doing his best to betray them, Macke thought angrily.
Wagner pointed down a narrow street leading away from the station. ‘He’s in the first few hundred yards, but he could be on either side,’ he said. ‘If we take the van any closer he’ll see us.’
‘All right, men, you know the drill,’ Macke said. ‘Wagner and Richter take the left-hand side. Schneider and I will take the right.’ They all picked up long-handled sledgehammers. ‘Come with me, Franck.’
There were few people on the street – a man in a worker’s cap walking briskly towards the railway station, an older woman in shabby clothes probably on her way to clean offices – and they hurried quickly past, not wanting to attract the attention of the Gestapo.
Macke’s team entered each building, one man leapfrogging his partner. Most businesses were closed for the day so they had to rouse a janitor. If he took more than a minute to come to the door they knocked it down. Once inside they raced through the building checking every room.
The pianist was not in the first block.
The first building on the right-hand side of the next block had a fading sign that said: ‘Fashion Furs’. It was a two-storey factory that stretched along the side street. It looked disused, but the front door was steel and the windows were barred: a fur coat factory naturally had heavy security.
Macke led Werner down the side street, looking for a way in. The adjacent building was bomb-damaged and derelict. The rubble had been cleared from the street and there was a hand-painted sign saying: ‘Danger – No Entry’. The remains of a name board identified it as a furniture warehouse.
They stepped over a pile of stones and splintered timbers, going as fast as they could but forced to tread carefully. A surviving wall concealed the rear of the building. Macke went behind it and found a hole through to the factory next door.
He had a strong feeling the pianist was in here.
He stepped through the hole, and Werner followed.
They found themselves in an empty office. There was an old steel desk with no chair, and a filing cabinet opposite. The calendar pinned to the wall was for 1939, probably the last year during which Berliners could afford such frivolities as fur coats.
