'We are. I just want to make sure we've got the right place. Half the houses in this road have been split into apartments. Her name's Samantha Evans. I want to check the name plates, find out what apartment she's in.'

He clambered out and closed his door, crossing the road, heading for the front entrance, double glass doors leading into a small atrium.

Jacobs scrambled out and followed, wanting to try and rein McEvoy in and make sure he didn't do anything he'd regret later. She caught him up as the door was opened by a man in his fifties wearing a red baseball cap and black, leather jacket, carrying a rucksack on one shoulder. The man stood to one side and ushered them in.

'Are you sure this is a good idea, Colm? We should wait for backup.'

'I've already told you, we're waiting for backup,' McEvoy snapped. 'I just want to make sure we're in the right place.' He stood in front a row of metal letterboxes, each with a narrow slot, a lock just below, and traced along them. 'Here, Samantha Evans,' he said, sounding vindicated. 'Flat 3c.'

He paused as something clicked into place in his mind. He wheeled round staring back out through the front door at the empty space. 'Shit!' he spat. 'That was him, come on!' He bolted for the exit. 'He was wearing a Red Sox cap, had side-burns.'

As McEvoy made it out of the doors a dark blue Fiesta appeared from the side of the apartment, turning left onto the road without stopping, accelerating away.

'Fuck!'

As he reached his own car the Fiesta was turning left onto the North Circular Road. He was never going to catch it. By the time he'd reached the turning, the Fiesta could have headed in any number of directions. He slammed a flat hand against the car roof, pulling his mobile free with the other.

A marked garda car pulled in behind him. Two uniformed guards stepped out.

'You've just fuckin' missed him!' McEvoy snapped. 'He was driving a dark blue Fiesta, registration plate 01-D-52. I didn't catch the rest. Driver's wearing a red cap, black jacket and blue jeans. He's wearing a disguise; he look's like he's in his mid-fifties. He turned left at the top of the road. Call it in.'

The two guards looked at each other.

'Now, for fuck's sake!'

One of them ducked back in to the garda car and grabbed the radio mic.

McEvoy pulled up Roche's number on his mobile phone.

'Roche.'

'He was at Samantha Evans' apartment,' he said without introduction, heading back over to the apartment block to where Kathy Jacobs was waiting, the other guard trailing after him. 'He was leaving as we were arriving. He was wearing a disguise, like O'Connell Street. Only this time he made himself look like a man in his fifties. He was driving a dark blue Fiesta, I've called the details in. I'm going up to her apartment to take a look around.'

'Jesus Christ. If he's still in Dublin, then we'll get him, don't worry. I'm already on my way back in.'

'Look, I've got to go.' McEvoy slid the phone into a pocket and tugged at the door handle, but it was locked. There was a bank of buzzers to the left. He started to press them in turn.

'Hello?' said a crackled voice through a speaker.

'An Garda Siochana, open the door,' McEvoy demanded.

'Pardon?'

'I said open the fuckin' door! Now!'

There was a loud buzz and McEvoy shoved the door open and entered the small atrium.

'Take it easy, Colm,' Jacobs warned. 'You've gone all hyper again.'

He ignored her, bursting into a stairwell and taking the steps two at a time to the top floor. He crashed through the fire door, glanced left and right, and headed right, back toward the front of the building. Apartment 3c was the only door on the left. He knocked loudly, waited a couple of seconds and knocked again.

'Shit. Right, come on,' he said to the uniformed guard, 'we need to get this open.'

'Are you sure that's a good idea?' Jacobs asked.

He ignored her again. 'On the count of three, we slam the door. Okay?'

'Sir.'

'Right. One, two, three.' McEvoy and the guard launched their shoulders onto the door. It creaked but stayed firm. 'And again.'

This time the door gave way, the two of them stumbling into a short hallway, a small utility cupboard to the left, a tumble dryer stacked on top of a washing machine. The hall opened out into an open-plan living room, a dining area and compact kitchen at one end, a sofa and a chair at the other near to French windows that led out onto a small balcony overlooking the street. A flat-screen television was placed on the wall opposite the sofa, Sky News broadcasting into the room, the sound audible but turned down low. Andrew McCormack's web photo stared out from the screen.

'If we'd got here before Bishop's broadcast we'd have got him,' McEvoy said frustrated, knowing that he was more angry with himself than Bishop. He'd let McCormack exit straight past them; didn't recognise him or give chase. Both unforgivable.

'Well, the whole city's looking for him now,' Jacobs said.

McEvoy headed to the door between the kitchen and dining area. It led into a short hall. To the right was a small bedroom, a double bed, its covers thrown back, taking up the majority of space. A long sausage dog draft excluder ran along the bottom of the door to the left, jammed tight into the crack. He took hold of the handle.

'I don't think that's a good idea, Colm,' Jacobs said, sniffing, her face draining of colour.

He looked back at her concerned face, pulled a tight smile of apology, and pushed it open. Even with his blocked sinuses, he knew the room stank of death and decay. He raised his hand up to his nose and mouth and stepped into the white tiled bathroom.

The sink was clean, sunk into a counter, bottles and make-up neatly arranged around it. The seat on the toilet was down, a pale blue shower curtain pulled across the length of the bath. He took hold of the edge of the curtain, his insides knotting, knowing what he was about to find. He swallowed hard and tugged the curtain back.

Samantha Evan's slight body lay in the bath, her hands tied to the bath hands, her feet to the taps. Almost every inch of skin below her chin had been sliced with a razor blade; thousands of short and long cuts, criss-crossing her body. The bath, the curtain and tiled wall were covered in splashes of blood.

McEvoy reeled around and dry heaved into the sink, then again, the burning vomit rising up his throat and out. He was aware of Jacobs edging into the bathroom, her scarf pulled up over her face. 'Don't,' he managed to mutter before retching again.

'Jesus Christ,' he heard Jacobs mutter. 'The poor girl.'

He wiped at his face with a hand and turned the tap on, scooping up water to his mouth and chin, washing the sick away. He staggered back out to the living room, his shirt and tie stained wet.

'Call a crime scene team in,' he said to the uniformed guard. 'There's a woman in the bath. Almost certainly McCormack's girlfriend, Samantha Evans. I'd say she's been dead a couple of days.'

The guard left the room, glad to get away from the apartment.

Jacobs joined McEvoy, her face stained with tears. 'He enjoyed killing her. The other deaths might have been quick, but he took his time with her. She died slowly. Very slowly.'

'If there was ever a case for bringing back the death penalty, this is it,' McEvoy said, his stomach still weak. Everything was going horribly wrong. It was turning into O'Connell Street Mark II. He felt hypertense; he didn't know whether he wanted to collapse in a heap of tears and grief or rage and rip and kick the room to bits. Instead, he pulled his mobile from his pocket. It rang before he could use it.

'Hello?'

'It's Paul Roche. That witness you interviewed yesterday, the drug addict, Karen, she's just been killed in that squat of hers. Sounds like it's Andrew McCormack. He's also seriously injured a man. Knife attack.'

'Fuck!' McEvoy spat, heading for the door, signalling to Jacobs to follow him. 'We've just found his girlfriend's body in her apartment. She died of a thousand cuts. Been dead a few days.'

'Jesus Christ! This is going from bad to worse. We need to catch this bastard before he kills anyone else. Every guard in the city's been mobilised, all leave cancelled. I'll meet you at the squat, okay.'

It had taken them less than two minutes to drive between the two sites. Two garda cars and an ambulance were already parked outside the derelict house, two guards taping off a perimeter. A gaggle of people were standing on the road and pavement watching the scene, trying to discover what had happened.

McEvoy jumped from the car and ran across the road. The boards had been pulled back, the front door forced open. He edged his way inside. A uniformed guard was standing at the bottom of the stairs.

'She up there?' McEvoy demanded.

The guard nodded and moved to one side. McEvoy took the steps two at a time and entered Karen's room.

She was lying on her back on top of the blanket in the corner of the room. Her tracksuit top was soaked with blood. The handle of a dagger protruded from her mouth, pinning her head to the floorboard beneath. Splashes of blood decorated the walls and pools had run across the floorboards, disappearing between the cracks.

Two paramedics were kneeling in the opposite corner, working on the man he'd last seen lying on the blanket with her. He had a deep cut on a bare arm, his chest bloody. His breathing was shallow, irregular.

'Is he going to be alright?' McEvoy managed to say.

'Touch and go,' one of them replied without looking up. 'The girl's dead. Nothing we could do to save her. We need to get him to a hospital, he's lost a lot of blood and I think one of his lungs has collapsed.'

'He's come full circle,' Jacobs said from behind him. 'She was Laura's friend and he thought she'd betrayed her; her death pact; betrayed him. She paid the price, dying as Laura did.'

One of the paramedics levered himself up off his knees and hurried from the room, brushing past them.

McEvoy couldn't disengage his eyes from Karen. She had probably known about Andrew McCormack from the start and yet she had lied for him while he continued to kill. Now he knew why. She'd known what the penalty would be; she'd known that she couldn't trust the guards to get to him first.

'Colm?' Jacobs prompted.

'What?' He tried to refocus.

'I think we should go; let the paramedics get on with their job. We've seen enough death for one day.'

He nodded agreement and they headed back out to the landing.

The paramedic and a guard were climbing the stairs carrying a stretcher. McEvoy and Jacobs stood to one side to let them pass and then descended in silence. A nervous looking couple in oddly matched tracksuits were visible in the front room, sitting on a sofa, staring at the blank wall.

'He's tying up loose ends,' Jacobs said as they reached the bottom. 'The girlfriend. Karen.'

McEvoy moved to the doorway and spoke to the couple.

'Did you call the ambulance and guards?'

'She did,' the young man said without turning his head, accusation and anger in his voice, unhappy that McEvoy and his colleagues had invaded their space.

'It was a man in a red baseball cap?'

The young woman nodded.

'Did a girl called Laura ever sleep here?'

The woman nodded again.

McEvoy massaged his forehead. McCormack was still loose in the city. He headed back out onto the street, aware that a thought was hovering just out of reach, teasing him. 'What did you say to me on the stairs?' he asked Jacobs, hoping her answer might prod it forward.

'I said, he's tying up loose ends.'

'Brady,' McEvoy said, the thought revealing itself. 'Shit! Maybe Brady's a loose end as well? This whole thing's been about Brady.' He started to run to his car, brushing past a man heaving a camera up onto his shoulder.

'This whole thing has been about Laura and McCormack,' Jacobs said, setting off after him.

McEvoy had started to reverse the car before Jacobs had got her door shut.

'Jesus, Colm!'

He stabbed at his mobile.

'Hello?'

'Dermot, where are you?' McEvoy demanded, swinging the car round.

'I'm in my office.'

'Lock the door and do not open it to anyone until I get there, you hear?'

'What's going on?'

'McCormack's on the run. He's killed his girlfriend and Karen. I'm afraid he might be coming after you.'

They passed Paul Roche racing up to the scene.

'For me?'

'He's trying to tie up loose ends. This whole thing's been about you. I'm worried he might be ...'

'He's ... he's on his way here?' Brady stuttered, interrupting, panic rising in his voice.

'I don't know where he is. Just lock the door and don't open it for anyone except me. Nobody. You understand? He's psychotic.'

McEvoy leant with his forehead resting against the mirror, the sink at his hips. All of his adrenaline and anger had dissipated to be replaced with a hollowness, an empty yawning in his chest and stomach; another low in a day of roller coaster emotions. He was mentally and physically exhausted, knowing that the day was only half over.

He pulled his head back an inch and tapped it against the mirror. He could have caught McCormack. He'd been less than two feet away when he'd held open the door to Samantha Evans' apartment block for them. If he'd followed Jacobs' advice and hadn't been in such a hurry to enter the building he would have recognised him, could have apprehended him or at least followed him. Karen would still be alive, her boyfriend not fighting for his life.

He pulled back from the mirror and stared at his grey and sunken face, his red eyes and thinning scalp. He was starting to look as Maggie had a couple of weeks before she died; his skin had the pallid cast of death to come.

His mobile phone rang. He rubbed at his temples, then reluctantly fished it out of his pocket. 'McEvoy.'

'It's Paul. Where the hell are you?'

'Sorry,' McEvoy said flatly. 'I wanted to make sure Dermot Brady was okay.'

'And is he?'

'Yeah, he's fine. I'm at the DHC offices right now. Any luck your end?'