The Laughing Policeman

'We also assume that the murderer fired three bursts. The first forward, from left to right, thereby shooting all those sitting in the front of the bus - marked here on the sketch as numbers one, two, three, eight and nine. Number one stands for the driver and number two for Stenstrom.'

'And then?'

'Then he turned around, probably to the right, and fired the next burst at the four individuals at the rear of the bus, still from left to right, killing numbers five, six and seven. And wounding number four - Schwerin, that is. Schwerin was lying on his back at the rear of the aisle. We take this to mean that he had been sitting on the longitudinal seat on the left side of the bus and that he had time to stand up. He would therefore have been hit last'

'And the third burst?'

'Was fired forward,' Martin Beck said. 'This time from right to left'

'And the weapon must be a submachine gun?' 'Yes,' Kollberg replied. 'In all probability. If it's the ordinary army type -'

'One moment,' Hammar interrupted. 'How long should this have taken? To shoot forward, swing right around, shoot backward, point the weapon forward again and empty the magazine?'

'As we still don't know what kind of weapon he used -' Kollberg began, but Gunvald Larsson cut him off.

'About ten seconds.'

'How did he get out of the bus?' Hammar asked.

Martin Beck nodded to Ek and said, 'Your department'

Ek passed his fingers through his silvery hair, cleared his throat and said, 'The door that was open was the rear entrance door. In all likelihood the murderer left the bus that way. In order to open it he must first move straight forward along the aisle to the driver's seat, then stretch his arm over or past the driver and push a switch.'

He took out his glasses, polished them with his handkerchief and went over to the wall.

'I've had two instruction sketches blown up here,' he said. 'One showing the instrument panel in its entirety, the other showing the actual lever for the front doors. On the first sketch the switch for the door circuits is marked with number 15 and the door lever with number 18. The lever is therefore to the left of the wheel, in front of and obliquely below the side window. The lever itself, as you see from the second sketch, has five different positions.'

'Who could make head or tail out of all this?' Gunvald Larsson said.

'In the horizontal position, or position one, both doors are shut,' Ek went on unperturbed. 'In position two, one step upward, the rear entrance door is opened, in position three, two steps upward, both doors are opened. The lever also has two positions downward - numbers four and five. In the first of these, the front entrance door is opened, in the second, both doors are opened'

'Sum up,' said Hammar.

'To sum up,' Ek said, 'the person in question must have moved from his presumed position by the exit door straight forward along the aisle to the driver's seat. He has leaned over the driver, who lay slumped over the wheel, and turned the lever to position two, thereby opening the rear entrance door. That is to say, the one that was still open when the first police car got there.'

Martin Beck picked up the thread at once.

'Actually there are signs showing that the last shots of all were fired while the gunman was moving forward along the aisle. To the left. One of them seems to have hit Stenstrom.'

'Pure trench warfare tactics,' said Gunvald Larsson.

'Gunvald made a very pertinent comment just now,' Hammar said drily. 'That he didn't understand a thing. All this shows that the murderer was quite at home in the bus and knew how to work the instrument panel'

'At least how to work the doors,' Ek said pedantically.

There was silence in the room. Hammar frowned. At last he said, 'Do you mean to say that someone suddenly went and stood in the middle of the bus, shot everyone there and then simply went on his way? Without anyone having time to react? Without the driver seeing anything in his mirror?'

'No,' Kollberg said. 'Not exactly.'

'What do you mean then?'

'That someone came down the rear stairs from the top deck with the submachine gun at the ready’ Martin Beck said.

'Someone who had been sitting up there alone for a while,' Kollberg said. 'Someone who had taken his time to wait for the most suitable moment'

'How does the bus driver know if there's anyone on the top deck?' Hammar asked.

They all looked expectantly at Ek, who again cleared his throat and said, 'There are photoelectric cells on the stairs. These in their turn send impulses to a counter on the instrument panel. For each passenger who goes up the front stairs the counter adds a one. The driver can therefore keep a check the whole time on how many are up there.'

'And when the bus was found the counter showed zero?'

'Yes.'

Hammar stood in silence for a few seconds. Then he said, 'No. It doesn't hold water.'

'What doesn't?' Martin Beck asked. 'The reconstruction.' 'Why not?' said Kollberg.

'It seems far too well thought out A mentally deranged mass murderer doesn't act with such careful planning.'

'Oh, I dunno,' said Gunvald Larsson. 'That madman in America who shot over thirty people from a tower last summer, he had planned as carefully as hell. He even had food with him.'

'Yes,' Hammar said. 'But there was one thing he hadn't figured out.'

‘What?'

It was Martin Beck who answered: 'How he was to get away.'

₁₂

Seven hours later the time was ten o'clock in the evening and Martin Beck and Kollberg were still at police headquarters on Kungsholmsgatan.

Outside it was dark and the rain had stopped.

Nothing special had occurred. The official word was that the state of the investigation was unchanged.

The dying man at Karolinska Hospital was still dying.

In the course of the afternoon, twenty helpful witnesses had come forward. Nineteen of them turned out to have ridden on other buses.

The only remaining witness was a girl of eighteen who had got on at Nybroplan and gone three stops to Sergels torg, where she had changed to the underground. She said that several passengers had got off at the same time as her, which seemed likely. She managed to recognize the driver, but that was all.

Kollberg paced restlessly up and down, eyeing the door repeatedly as if expecting someone to throw it open and rush into the room.

Martin Beck stood in front of the sketches on the wall. He had clasped his hands behind him and rocked slowly to and fro from sole to heel and back, an irritating habit he had acquired during his years as a constable on the beat long ago and which he had never been able to get rid of since.

They had hung their jackets over the chairbacks and rolled up their shirtsleeves. Kollberg's tie lay on the desk where he had tossed it, and although the room was not particularly warm he was perspiring in the face and under the arms. Martin Beck was seized with a long, racking cough, then he put his hand thoughtfully to his chin and went on studying the sketches.

Kollberg stopped his pacing, looked at him critically and declared, 'You sound awful.'

'And you get more and more like Inga every day.'

And just then Hammar threw open the door and marched in.

'Where are Larsson and Melander?'

'Gone home.'

'And Ronn?'

'At the hospital.'

'Oh yes, of course. Heard anything from there?' Kollberg shook his head. 'You'll be up to full strength