The balaclava began to move where the mouth would have been, like a Bigfoot doll: 'This is a hold-up. Nobody move!'

He hadn't raised his voice, but in the small, compact bank building it was as if a cannon had gone off. Harry studied Stine. Above the distant drone of traffic he could hear the smooth click of greased metal as the man cocked the gun. Her left shoulder sank, almost imperceptibly.

Brave girl, Harry thought. Or maybe just frightened out of her wits. Aune, the psychology lecturer at Oslo Police College, had told them that when people are frightened enough they stop thinking and act the way they have been programmed. Most bank employees press the silent robbery alarm almost in shock, Aune maintained, citing post-robbery debriefings where many could not remember whether they had activated the alarm or not. They had been on autopilot. In just the same way as a bank robber has programmed himself to shoot anyone trying to stop him, Aune said. The more frightened the bank robber is, the less chance anyone has of making him change his mind. Harry was rigid as he tried to fix on the bank robber's eyes. Blue.

The robber unhitched a black holdall and threw it over the counter. The man in black took six paces to the counter door, perched on the top edge and swung his legs over to stand directly behind Stine, who was sitting still with a vacant expression. Good, Harry thought. She knows her instructions; she is not provoking a reaction by staring at the robber.

The man pointed the barrel of the gun at Stine's neck, leaned forward and whispered in her ear.

She hadn't panicked yet, but Harry could see Stine's chest heaving; her fragile frame seemed to be struggling for air under the now very taut white blouse. Fifteen seconds.

She cleared her throat. Once. Twice. Finally her vocal cords came to life:

'Helge. Keys for the ATM.' The voice was low and hoarse, completely unrecognisable from the one which had articulated almost the same words three minutes earlier.

Harry couldn't see him, but he knew that Helge had heard what the robber had said and was already standing in the office doorway.

'Quick, or else…' Her voice was hardly audible and in the following pause all that could be heard in the bank were the soles of August Schulz's shoes on the parquet flooring, like a couple of brushes swishing against the drum skin in an immeasurably slow shuffle.

'…he'll shoot me.'

Harry looked out of the window. There was often a car outside, engine running, but he couldn't see one. Only a blur of passing cars and people.

'Helge…' Her voice was imploring.

Come on, Helge, Harry urged. He knew quite a bit about the ageing bank manager, too. Harry knew that he had two standard poodles, a wife and a recently jilted pregnant daughter waiting for him at home. They had packed and were ready to drive to their mountain chalet as soon as Helge returned. At precisely this moment Helge felt he was submerged in water, in the kind of dream where all your movements slow down however much you try to hurry. Then he came into Harry's field of vision. The bank robber had swung Stine's chair round so that he was behind her, but now faced Helge. Like a frightened child who has to feed a horse, Helge stood back and held out the bunch of keys, his arm stretched to the limit. The masked man whispered in Stine's ear as he turned the machine gun on Helge, who took two unsteady steps backwards.

Stine cleared her throat: 'He says open the ATM and put the money in the black holdall.'

In a daze, Helge stared at the gun pointing at him.

'You've got twenty-five seconds before he shoots. Not you. Me.'

Helge's mouth opened and closed as though he wanted to say something.

'Now, Helge,' Stine said.

Thirty seconds had passed since the hold-up began. August Schulz had almost reached the front door. The branch manager fell to his knees in front of the ATM and contemplated the bunch of keys. There were four of them.

'Twenty seconds left,' Stine's voice rang out.

Majorstuen police station, Harry thought. The patrol cars are on their way. Eight blocks away. Friday rush hour.

With trembling fingers, Helge took one key and inserted it in the lock. It got stuck halfway. He pressed harder.

'Seventeen.'

'But…' he began.

'Fifteen.'

Helge pulled out the key and tried one of the others. It went in, but wouldn't turn.

'My God…'

'Thirteen. Use the one with the bit of green tape, Helge.'

Klementsen stared at the bunch of keys as though seeing them for the first time.

'Eleven.'

The third key went in. And round. He pulled open the door and turned towards Stine and the man.

'There is one more lock to open…'

'Nine!' Stine yelled.

Helge sobbed as he ran his fingers across the jagged edges of the keys, no longer able to see, using the edges as Braille to tell him which key was the right one.

'Seven.'

Harry listened carefully. No police sirens yet. August Schulz grasped the handle of the front door.

There was a metallic clunk as the bunch of keys hit the floor.

'Five,' Stine whispered.

The door opened and the sounds from the street flooded into the bank. Harry thought he could hear the familiar dying lament in the distance. It rose again. Police sirens. Then the door closed.

'Two, Helge!'

Harry closed his eyes and counted to two.

'There we are!' It was Helge shouting. He had opened the second lock and now he was half-standing, pulling at the jammed dispensers. 'Let me just get the money out! I-'

He was interrupted by a piercing shriek. Harry peered towards the other end of the bank where a woman stood staring in horror at the motionless bank robber pressing the gun into Stine's neck. She blinked twice and mutely nodded her head in the direction of the pram as the child's scream rose in pitch.

Helge almost fell backwards as the first dispenser came free. He pulled over the black holdall. Within six seconds all the money was in. Klementsen zipped up the holdall as instructed and stood by the counter. Everything had been communicated via Stine; her voice sounded surprisingly steady and calm now.

One minute and three seconds. The robbery was complete. The money was in a holdall. In a few moments the first police car will arrive. In four minutes other police cars will close off the immediate escape routes around the bank. Every cell in the robber's body must have been screaming it was time to get the hell out. And then something happened which Harry didn't understand. It simply didn't make any sense. Instead of running, the robber spun Stine's chair round until she was facing him. He leaned forward and whispered something to her. Harry squinted. He would have to go and get his eyes checked one of these days. But he saw what he saw. She was focused on her faceless tormentor; her own face went through a slow, gradual transformation as the significance of the words he whispered to her appeared to sink in. Her thin, well-tended eyebrows formed two 's's above eyes which now seemed to be popping out of her head; her top lip twisted upwards and the corners of her mouth were drawn down into a grotesque grin. The child stopped crying as suddenly as it had begun. Harry inhaled sharply. Because he knew. It was a freeze-frame, a masterly image. Two people caught for a split-second as one informed the other of the death sentence; the masked face two hands' widths away from its helpless counterpart. The Expeditor and his victim. The gun is pointed at her throat and a small golden heart hanging from a thin chain. Harry cannot see, but nevertheless he can sense her pulse pounding beneath the thin skin.

A muffled wail. Harry pricks up his ears. It is not police sirens, though, just the telephone ringing in the next room.

The masked man turns and peers up at the surveillance camera hanging from the ceiling behind the counters. He holds up one hand and shows five black gloved fingers, then closes his hand and extends his forefinger. Six fingers. Six seconds too long. He turns towards Stine again, grasps the gun with both hands, holds it at hip height and raises the muzzle towards her head, standing with his legs slightly apart to withstand the recoil. The telephone keeps ringing. One minute and twelve seconds. The diamond ring flashes as Stine half-raises her hand, as though waving goodbye to someone.