"Every investigation is hindered by noise massive amounts of data, the vast majority of which are irrelevant, some of which are false, and some of which are positively misleading. Witnesses can be remarkably unreliable, remembering things incorrectly or remembering things that never happened. And often the murderer himself will seek to deflect attention, disrupt the record, and send the police on a wild goose chase, trailing along a track of lies."

6a. Let them think you have made mistakes.

6b. Plant false evidence to set false trails point the police at innocent people.

6c. Mess with the profiling set false patterns.

6a-c give false hope, create blind avenues, and buy time, space, confusion and doubt. Remember, the media are your friends. They will report nonsense and undermine the police investigation if the results are not to the public's satisfaction.

Master rule: Do not underestimate the police they are smart, they have experience, there are many of them, and they have a lot of resources.

'This is about Brady,' McEvoy said, stating the obvious. 'He's letting us know that he laid a false trail. Jesus. He thinks he's so feckin' clever.'

'Can I take a look,' Jacobs asked.

McEvoy passed her the bag.

Whelan's phone rang as the pathologist's van appeared over his shoulder, slowly making its way down the laneway towards them.

'Whelan ... uh-huh ... I'll be there now.' He returned the phone to his pocket. 'The victim was staying at the hotel,' he stated flatly.

'You go over,' McEvoy instructed. 'I'll follow in a minute.'

Whelan nodded and set off at a brisk pace along the path.

The van came to a halt. Billy Keane pushed open the driver's door sending it crashing into a barbed wire fence. He pulled a 'sorry' face through the windscreen, levered himself out and lurched towards the back of the van. Elaine Jones climbed out of the passenger door and came round to meet them.

'Elaine.'

'Colm.' She waved her hand, calling him towards her. 'Come on, like you promised.'

McEvoy could feel his face flush. He stepped forward, leaned down and kissed her on both cheeks. 'I'm still training him up,' she said to Kathy Jacobs. Followed by, 'You're freezing. Where the hell's your coat? You'll catch your death out here with this wind. And you're smoking again, Colm. I can smell them. The damn things will kill you. They killed Maggie and they'll kill you and where would that leave Gemma? Are you going to introduce me,' she added before he could answer.

'Er, right, sorry,' he stuttered, still reeling from Elaine's rebuke, knowing that she was right, but unhappy to be reminded. 'Dr Kathy Jacobs, Professor Elaine Jones. Dr Jacobs is a ...'

'I know all about Dr Jacobs,' the pathologist said, shaking the profiler's hand. 'She's making quite a name for herself these days. Someone high up must have pulled a few strings for you, Colm.'

McEvoy cut across the near empty terrace, the hotel guests having retreated to the sanctuary of the hotel, and entered through a bar. He wandered into the busy reception area. Whelan was standing at the front desk talking to a hassled-looking woman in her mid-thirties.

'How's it going?' he asked, interrupting, glad of the warmth.

Whelan rolled his eyes in response.

'I just want to know when we're going to be able to get things back to usual,' the woman said to McEvoy. 'Guests need to leave, the shift is meant to change, the rooms need cleaning, deliveries are being turned away. We need to try and get things back to something like normal.'

'There's nothing normal about this morning, Miss. One of your guests has been murdered across in the bay. Her head is missing its face,' he said callously, ignoring the fact that her request was entirely reasonable and she was no doubt under a lot of pressure from guests and staff forced to stay so they could be interviewed. 'Look, don't worry; every sick bastard for miles around will come traipsing through here in a few days' time wanting to see where she was killed. You'll make up on any lost business then.'

'I'm sorry. Look, that's not what I meant ... I didn't mean to ...' she trailed off embarrassed and flustered.

'What have you found out about the victim?' McEvoy asked Whelan.

'I've already told the inspector,' the woman replied, unsure whether McEvoy was still addressing her.

'And now I want you to tell me,' McEvoy said, turning back to the woman, frustrated she'd answered a question he hadn't asked her.

'We ... we think it's Shirley Hamilton,' her face flushed red. 'She's a Northerner, lives in Belfast. She was doing contract work out at the airport; staff development training, I think. She stays here rather than the airport as she likes to run along the coast. She runs marathons. One of our bar staff does as well. They know each other from races. We all sponsored her last year when she ran in the New York marathon. I can't believe this has happened. She was great craic. Always had a joke.'

'Did anyone see her head out this morning?'

'One of the reception staff saw her go.' She nodded at two women sat at a coffee table. 'She set off around 6.30.'

'And can you confirm what she was wearing?'

'Ausra,' the woman called out, gesturing to the younger of the pair.

The woman approached. 'Yes?'

'Can you remember what Ms Hamilton was wearing when she went out for a run this morning?'

'Ms Hamilton? I think she was wearing a ... yes maybe a red coat and blue trousers,' she replied with an East European accent. 'She had her hair in ...' She gestured with her hands.

'Pigtails,' McEvoy said.

'Pigtails?' the woman repeated, confused.

'Her hair in two strands,' McEvoy said.

'Yes, yes, two strands.'

'Ausra's from Lithuania,' the older woman explained.

'Is she okay?' Ausra asked. 'Ms Hamilton?'

McEvoy pursed his lips. 'No, I'm afraid she's dead. She was killed while she was running. We're investigating her death.'

Ausra nodded, the rumours confirmed.

McEvoy's phone rang. He signalled apology and stepped away from the counter. 'McEvoy.'

'I've just spoken to Brady,' Plunkett said. 'He was admitted to St Ita's when he was 17. He kind of went off the rails a bit. He had severe manic depression. He's been on lithium ever since. He was an in-patient for seven months. If the killer's one of his co-patients he has no idea who it is. He can't really remember them and he hasn't kept in touch with any of them either.'

'Right, okay. Well, at least the location makes sense. I want you to ask him to come in again. We need to pick his brains, see if we can dislodge something useful. See if he can come in for two o'clock. We'll hold a team meeting then afterwards, around three.'

'I'll talk to him again. The meeting will have to be better than this morning's. Charlie Deegan was a feckin' disaster. He basically said he was going to run his investigation and feck the rest of us,' Plunkett stated, saying what he'd wanted to report in his last phone call.

'For God's sake,' McEvoy said, massaging his face. 'I thought I told you ... It doesn't matter, I'll deal with it when I get back. Just keep plodding away for now. I'll be in after the press conference at one o'clock.' He ended the call and stepped back over to the reception desk. 'Do you have a cigarette machine?' he asked a hint of desperation in his voice.

McEvoy reversed out onto the road, swung the car around and headed back down the road towards Donabate. He sucked on his plastic cigarette and then held it between his index and middle finger, his hand resting on the steering wheel. 'So you said you'd had a go at constructing a basic profile?' he asked, breaking the ice.

Kathy Jacobs brushed her hair off her face and twisted her body in the seat towards him. She'd underdone the buttons on her coat and unwound the scarf to reveal a dark grey business suit over a pale blue shirt, the skirt ending at her knees. 'I've had a go on the basis of what was sent to me some case notes and photos,' she said in her soft, Scottish lilt. 'I'll be able to flesh it out once I've seen more of the files and visited the crime scenes.'

'But you can give me the bare bones of it now?'

'As long as you appreciate it's a preliminary profile, then yes, no problem.'

He nodded his assent.

'As you probably know,' she started, 'serial killers fall into two general types disorganised and organised. Disorganised killers are often paranoid schizophrenics. They have a hard time distinguishing reality from fantasy. They end up killing people not so much because they want to, but because at some level they're driven to. Voices tell them to, or they over-react to a set of circumstances beyond their control. They're usually people known by the system their illness is diagnosed and they live with their parents or in institutions or on the street.

'An organised killer is an entirely different proposition. They know what they are doing and they prepare for their crimes. Whereas disorganised killers are rarely in control of their actions, and any rape and murder usually takes place in a frenzy of violence, organised killers plan things in advance, they collect together everything they need, they clean up after themselves to avoid being caught, and their violence can be calmly and sadistically stretched out over days or weeks. They themselves were probably a victim of violence when a child, developing heightened capacities for delusion, anger, denial and revenge. As adults they're driven by a deep psychosis that they try to manage and feed victims to while trying to make sure they get away with their crimes. Unlike disorganised killers, they know what they do is considered highly deviant by the rest of society.

'In both cases, but particularly for organised killers, the murders are nearly always sexually motivated or expressed. They're driven by a desire to sexually humiliate and conquer their victims. That doesn't mean rape, it could simply be tying up and torturing the victim; but it does mean sexually dominating or punishing them in some way. The murders are usually highly choreographed and the victims, to some degree, are merely disposable props in their own theatre. The victims also usually follow a pattern the same age, body build, hair colour, and so on, so their play can be re-performed endlessly.

'The murders you're investigating are highly organised, but they differ substantially from the kinds of murder most serial killers commit. They're not about sex; at least not all of them appear that way. The victims vary in profile and the killings, with the exception of Laura Schmidt were quick and perfunctory and he left the scene in a hurry. They were almost like assassinations rather than serial killings.

'And your killer is similar to and yet quite different to the usual kind of people who would generally commit such crimes. I doubt, for example, he has a record for sexual offences. I also doubt he was the victim of an abusive household or sexual abuse as a child. He might well though have caught and tortured small animals when he was growing up. He would have liked the power of life and death; of controlling their destiny. There would have been some manifestation of his sadistic tendencies, however expressed.'

'So what are the murders about?' McEvoy asked impatiently, glancing over at her.

'I'm getting to that,' Jacobs said calmly, ignoring McEvoy's testiness. 'I want you to understand that The Raven is different. He doesn't seem to be driven by a sexual psychosis that he struggles to control. He kills because he can and because he wants to. Not because he wants to commit some kind of sexual revenge. And he has almost certainly killed before this week. The Rule Book is a public expression of his confidence in his ability to kill and get away with it.'

'He's killed before,' McEvoy repeated.

'My professional opinion is several times. You don't start your killing spree by undertaking anything as complicated as he's attempting. He's drawing on experience and a self-assurance that he knows what he is doing. The Rule Book explains why he's got away with them. Why he's confident that he'll continue to get away with them.'

'Jesus,' McEvoy muttered, shaking his head.

'He probably appears little different from everyone else,' Jacobs continued, adjusting the lie of her seatbelt, 'perhaps married, with children; a pillar of the local community. That said, I think he's someone who is very confident, very smart, and probably very arrogant; someone with a high degree of detached control, a lot of patience, but also a short fuse. He's prepared to spend a lot of time planning, thinking through each crime, making sure he knows exactly how he's going to perform it, on whom, how he will get away, how he will dispose of the evidence, and so on. He's educated he can write well, he can think through a large project, and he's researched how you'll try and catch him, taking the necessary precautions using gloves, protective clothing, disguises, whatever's needed. He likes the challenge of killing in public places but he's a calculated risk taker.

'He was relatively cautious to begin with,' Jacobs explained. 'The murders happened under the cover of darkness and there were large gaps between them. There were 22 hours between the first and second killings. 24 hours between the second and third. Only 16 hours between the third and fourth, and it took place in broad daylight, albeit in an isolated rather than public spot. By the fifth he's grown more confident again, killing in broad daylight in a busy, public place.

'The only anomaly relates to how he killed Laura Schmidt. All of the others he attacked and knocked unconscious before they knew what was happening. With Laura there's no sign of attack. I've been thinking about that. I think he knew that she wouldn't fight or struggle. I don't know why, but I think she trusted him.'

'You think that she knew him?' McEvoy asked, his brow furrowed with skepticism. 'That maybe they were friends?'

'I'm not sure friends is the right word. And I'm only going on the case notes here. I think they'd established some kind of bond; some kind of understanding whereby she took him into her confidence and him likewise. I think she wanted to die and I think she let him kill her.'

'A pact?'

'Perhaps,' she hedged. 'It's only speculation, but that's my reading given the case notes. I think she might have provided the impetus, the spark, for this whole killing spree. If he's going to kill one person, he might as well use it for other ends. He planned the other murders to follow hers.'

'Sounds a bit far fetched, doesn't it,' McEvoy said doubtfully. 'He meets a homeless girl, he befriends her, she asks him to kill her, and then he thinks, "Well, if I kill one I might as well kill seven. And while I'm at it, I'll write a book on how to commit the perfect murder",' he finished sarcastically.

'As I said, it's speculation and I'd need to talk to people who knew her and see more of the crime scene analysis, but it would explain why she seemingly just welcomed the killing and why he carried on with several more,' Jacobs persisted.

McEvoy scrunched his face up and shrugged his shoulders signalling that he wasn't convinced. 'It's a possibility, I guess,' he said. 'She could have also been too pissed to stop him; to know what the hell was going on.'

'There's that as well,' she conceded. 'There's something about that death though; something that seems at odds with the other murders. It just doesn't seem to make sense. Even if she was drunk, you'd have thought she'd have made some effort to save herself?'

'As you said, maybe she was happy to die? Had enough of life?'

'It's more than that. She undressed, laid on the bed, and accepted the sword through the mouth. It wasn't just that she accepted death, she was prepared to make it look like a sacrifice.'

'You said he had a short fuse?' McEvoy asked, trying to steer the conversation back round to The Raven. Laura's death still gnawed away at him and he wanted time to think about Kathy Jacobs' thesis.

'You saw the body back there, Colm. All the other killings were clinical, mechanical. With the exception of Laura, he knocked them unconscious and then dispatched them. Okay, some of them were a little elaborate the sword, the paint, the cut off toes but they were all performed calmly and efficiently.

'He'd battered that woman to death. Not clinically or systematically, but with a violent rampage, hitting her repeatedly and without pattern. Probably wasn't even aware of what he was doing, though he regained some composure at the end. Made sure she ended up face down in the rock pool to die as he intended by drowning and then cleaned up after himself, taking whatever it was he hit her with, and leaving the card and chapter, though he just seemed to throw the latter away. For a brief period he lost self-control.

'My feeling is it was because the attack probably didn't go to plan. He'd spent a lot of time preparing it and maybe she didn't play her part properly. Maybe he forgot some detail. I don't know. Whatever it was, it triggered a violent reaction. More violent more frenzied and less calculated,' she qualified, 'than the other attacks.

'That's not to say that he felt any more compassion for his other victims than her. I think he sees his victims as legitimate targets in the game he's playing. Even Laura. They're simply disposable objects, not living, breathing human beings. I doubt he has any real feelings for them or anyone else. The only thing that matters is himself.

'He's selfish and he's egotistical. And there's no doubt he is a psychopath. But he wouldn't recognise that in himself. He would see himself as rational and reflexive able to self-analyse and internalise his thoughts and emotions. He knows he's not like everyone else, but he also knows what he needs to do to appear like they do. To him, though, all other people are inferior.

'My sense is that he's almost certainly an over-achiever and he relishes in his own perceived superiority. But he feels that this superiority is not sufficiently recognised by others; that he's not receiving his fair dues. Perhaps he's being blocked from promotion at work, or people are simply not taking him or his ideas seriously? I don't know. What I do think, however, is that he has a desire to prove them wrong, to demonstrate how much smarter than them he is. This is what these killings are all about ego.'

'He could have written his book without killing six people,' McEvoy said flatly.

'But he wouldn't have been able to prove that it worked. He wants the recognition, the acknowledgement, that he's a genius.'

'He's a sick bastard,' McEvoy said without thinking.

'I agree, but so far he's got away with the killings and it appears like he really is an evil genius. And if you don't catch him he will kill again,' Jacobs continued. 'He'll start a new campaign. A new challenge. Maybe not for a while six months or a year. He'll lie low, then he'll start planning a new book, a riddle, a different puzzle; something. But he will surface again; that you can be sure of.'

'You sound very confident.'

'Read the literature, Colm. There are very few serial killers who stop killing once they start. They might pause or go dormant for a while, but they inevitably start again. And he'll feel his audience will want an encore.'

'His audience?'

'The public. The media. This is the biggest story on the planet at the moment. Every news channel, every newspaper, have reporters here. The whole world is watching, waiting to see how it ends.'

McEvoy nodded and stared out of the windscreen at the road ahead, mulling over Kathy Jacobs' assessment. Whilst informative and useful, if anything it made the investigation seem more daunting. The Raven, while probably arrogant, seemed to the rest of the world exactly like them. Except of course he wasn't; he was a psychotic egotist.

The mirror was cracked, the line running through his face, the halves not quite matching. Somehow McEvoy felt it looked appropriate. He wedged a finger between his collar and neck and jiggled it about uncomfortable with the fit now the tie was tightened. He straightened the lapels on the new uniform and ran a hand over his hair. It seemed strange to be wearing a suit that fitted perfectly after the looseness of his usual, oversized clothes. Dressed like this there was a danger people might actually start saluting and calling him Sir.

He left the room and joined Bishop, the Assistant Commissioner, Kathy Jacobs and three members of the press team in the meeting room with the Yeats prints. The press team were already sitting in a row along one side of the table, playing with their pencils and pads, worried looks etched on their faces. The morning's newspapers were laid out before them. The other three were standing together near the window, the Assistant Commissioner holding court. He had the look of a brawler, someone you wouldn't want to meet in a dark alley thick dark hair, ruddy cheeks, big barrel chest, and giant hands with chunky fingers.

They stopped their conversation, their small circle opening to face him.

'Colm,' the Assistant Commissioner said with a solemn face, moving forward to shake his hand.

'Sir,' McEvoy replied while trying to keep his hand stiff, resisting the crushing vice.

'Shall we get started?' The Assistant Commissioner sat at the head of the table. 'We'll have to leave for the Burlington in twenty minutes or so get ourselves set up. No doubt they'll be even more of the feckers than there were yesterday.'

Bishop sat to his right. Kathy Jacobs skipped a seat, forcing McEvoy to sit at the far end of the table facing the AC and visible to all. He was uncomfortable with Jacobs being there, but nobody else seemed to mind.