Brady shook his head and looked down at the table.

'It's important, Dermot,' Jacobs added. 'He needs to be stop-ped.'

'Give me some paper and a pen. You better run through that description again.'

There were five names on Brady's list, two of which he'd crossed out. Two from his church who both worked in financial services, one from a government department that the DHC had had a run-in with, a warden from Mountjoy prison, and a friend's brother who had unsuccessfully run for TD in the last election. Amusingly, he had thought Charlie Deegan should have been on it. 'A Class A wanker, a bully with aspirations above himself,' was how Brady had described him.

He remained adamant that while the five people on the list had most of the qualities described by Kathy Jacobs, he didn't believe any of them to be The Raven, and two of them probably didn't know that much about him. They were people he'd met a couple of times at most but who'd left a memorable impression because of their self-centredness and conceit. There were others, but he couldn't remember their names.

'I'll get someone on these right away,' McEvoy said to Jacobs, the door to the interview room closing behind them. 'Arrange for them to be interviewed. See if we can eliminate them from the enquiry.'

Dr John pushed himself up off the corridor wall as they turned towards him. It was strange to see McEvoy in a uniform. And something that fitted properly. He was barely recognisable except for the sunken and worn out face.

'I've cracked the code,' he said enthusiastically, holding out a bit of paper. 'Should have cracked it ages ago, but I was playing around with letters not numbers. I thought it would spell out a name or something. Anyway, it's a location reference. Latitude and longitude like in the Phoenix Park.'

McEvoy took the bit of paper, glanced down at it and back up to Dr John. 'Are you sure you've got this right?'

'Yeah, yeah, look.' He took the sheet of paper back and held it up against a wall so they could all see. 'With each chapter he gave us two letters. For example, Chapter One M: Choosing a victim R. In total there are six chapters, giving us 12 letters. All he's done is used a simple substitution code.' He tapped the sheet.

a b c d e f g h i j k l m 3 4 5 6 7 8 9 0 1 2 3 4 5.

n o p q r s t u v w x y z 6 7 8 9 0 1 2 3 4 5 6 7 8.

'If all the letters associated with the chapter bit are grouped together you get MAIXLH. If all the letters with the chapter titles are grouped you get RDKUWC. If you put them into the substitution code, you get a latitude and longitude.' He tapped the sheet again, smiling.

MA IX LH RD KU WC.

53,16,40 06,33,55.

'53,16,40 North, 06,33,55 West. It's a cemetery in Oughterard out in Kildare. Between Celbridge and Naas. Not far from Straffan.'

'If it's just a simple substitution code, why haven't the papers or their readers already worked it out?' McEvoy asked.

'Because the chapters sent to the media didn't contain the extra letters. They were only in the chapters left at the murder scenes. They were a puzzle for us to solve. He was testing us.'

'Jesus! For God's sake. Come on, let's get moving.' McEvoy hurried towards the exit, his skin tingling, stomach churning, with a sickening realisation that he should have had more people working on the code. 'I've got a map in the car, we can make some phone calls on the way.'

They sped along the narrow road riding the line of a low ridge, to the left the foothills of the Wicklow Mountains rolled green and brown fields, dotted with trees, one-off housing and farms. Low cloud obscured the hills beyond. Two garda cars were parked ahead beside a couple of houses, just before the road dipped away to the left, down toward the busy N7 carrying traffic between Dublin, Cork and Limerick.

Two guards watched from the entrance of a laneway, their caps down low, collars up, hands hidden by their coat sleeves, as McEvoy parked in behind the cars. He levered himself out and hurried towards them, the stiff, cold breeze blowing at his back, shoving him forward. As he neared he could see the large iron gates painted black, 'OUGHTERARD CEMETARY' welded into the iron work, painted white. To the side was a narrow swing gate.

'Detective Superintendent McEvoy,' he introduced himself. 'I don't want anyone else up this laneway unless they're a guard, that clear?'

'Sir,' muttered the elder of the two, sharing a quizzical look with his colleague.

'Good.'

Kathy Jacobs and Dr John joined him. 'You're going to need this,' she held out his coat.

'Thanks.' He looked down at his pristine uniform and shrugged the windproof jacket on. He hoped to God he wasn't going to have to trample across fields. Bishop would have a fit.

They slipped through the narrow side gate and headed up the gravel laneway. A hundred metres or so up ahead, through the trees to the left and beyond a stone wall, he could see a stunted round tower and what looked like a ruined church. As they neared, it was apparent that half the church was missing a roof and a small tower adjoining the main structure had peeled away, it being held upright by two concrete supports. The cemetery was surrounded by a high stone wall, the entrance blocked by a padlocked gate. A set of stone steps led up and over the structure, two guards standing at its base looking cold and bored.

'You had a look round?' he asked.

'We were told to wait outside,' one of them answered.

McEvoy climbed the steps and looked into the cemetery. It wasn't large, perhaps 60 metres long by 30 metres wide. The stone wall extended all the way round, beyond it to the right the land sloped away onto the Kildare plain, hedgerow plots stretching to the horizon. The ruined church was immediately inside the gate to the left, the stunted round tower in the far corner behind it. The ground in front of him undulated in soft rounded mounds, the thick grass relatively free of gravestones, which grew in number towards the far wall.

McEvoy turned round and looked down at the others, the cold wind whipping into his face. 'I guess we'd better get started. We need to search this cemetery. The problem is we've no idea what we're looking for. It might be obvious or it might be more subtle. He could be pointing us to a family name, perhaps his own, perhaps a victim's, or maybe he's left something here for us, I don't know. If you see something that you think might be of interest call out and we'll take a look. And be careful where you tread, okay I don't want to mess up any evidence. John, you take here to the left and the church. You two take this side,' he instructed the two guards, pointing to the right. 'Dr Jacobs and myself will take the far end. Clear?'

The four heads nodded their assent.

He swung his leg over the top of the wall and descended into the cemetery, the wind immediately dying down with the protection of the high barrier. He waited for the others and set off with Kathy Jacobs.

'There's a lot of history here,' Jacobs said. 'This place must go back centuries. These mounds are all family vaults and the stones ahead look ancient.'

'Hardly packed though, is it?' McEvoy replied. 'There are only a few plots.' He looked at the names on the stones Garnett, Higgins, Christian, Carroll, Farrell, Hanlon, Comerford, Cahill Anglo-Irish sounding names; most dying in the late 19th and early 20th centuries.

'Sir!' Dr John called from the entrance into the unroofed part of the church.

'What?'

'There's an envelope here. Underneath a rock.'

McEvoy hurried to the archway. Dr John pointed down to the gravelled ground three steps below. Next to a gravestone embedded in the side of the ruined wall a cream envelope, wrapped in a clear plastic bag, peeked out from beneath a flat rock. McEvoy searched his pockets trying to find a pair of rubber gloves, knowing they were in the jacket of his suit.

'For God's sake! Can you run down to the ...'

He trailed off as Dr John held up a thin box. 'For emergencies.'

They descended to the church's floor, McEvoy tugging on the gloves. He lifted the rock and retrieved the envelope. He teased open the bag and plucked up the unsealed flap. It contained a single sheet of paper. He pulled the sheet free inside the bag and unfolded it, a crumpled five-euro note dropping free. He read the note out loud.

This is my one concession. If you are in time, this is your chance to cut the book short and make my fame. If you are too late, then I am already safe in my anonymity. Of course, you could be on time and I could still manage to kill the final victims and get clean away. Enjoy a pint of the black stuff on me.

'There's a picture of a raven at the top. At the bottom he lists a series of latitudes, longitudes and dates.' He showed the others.

53,11,56 N, 06,17,32 W, 13th April 53,22,68 N, 06,36,01 W, 14th April 53,21,30 N, 06,19,33 W, 15th April 53,27,59 N, 06,43,42 W, 16th April 53,20,50 N, 06,15,21 W, 17th April 53,28,58 N, 06,06,36 W, 18th April 53,20,59 N, 06,15,37 W, 19th April 'No doubt they're the locations of all of the murders,' McEvoy said frustrated. 'If this has been here all week anyone could have found it! It's like he wants to be caught.'

'It's hardly on the beaten track though, is it?' Jacobs said. 'I doubt anyone's been here recently, and even if they had it's unlikely they would have picked up what looks like a bit of litter and ripped it open.'

'And even if I'd broken the code earlier,' Dr John added, 'we couldn't have found his list until this or the previous murder. The grid reference was too coarse. It would have covered a huge area. Several square miles.'

'But if we, or someone else, had found it, we could have been waiting for him,' McEvoy muttered, shaking his head.

'We still can be,' Dr John said, raising his eyebrows. 'It tells us exactly where the last murder's going to happen. We just need to work out where that grid reference is.' He stabbed his finger at the bag.

'Jesus Christ!' McEvoy said, half in excitement, half disbelief. 'He's going to let us catch him. It's like you predicted,' he said to Jacobs, 'he wants to be caught. He wants the fame. His ego's too strong to let him simply walk away. That's why he's left us the clues and this note.'

'That, or he wants to prove how smart he really is,' Jacobs replied neutrally. 'He says it himself. "Of course, you could be on time and I could still manage to kill the final victims and get clean away." Maybe he's confident he can kill his last target right under your noses and walk away scot free.'

'We need to find out where that grid reference refers to,' McEvoy said, moving back towards the entrance.

'Well, it seems he has a sense of humour,' Dr John said, stopping him. 'The five-euro note. "Enjoy a pint of the black stuff on me." This is why he left the envelope here. It's kind of a joke. A sick joke.' He tapped the gravestone embedded in the wall. 'Have you seen whose grave this is?'

McEvoy stepped back and peered at the engraving on the pale grey rock, difficult to read in the pale light.

In the adjoining Vault are the mortal remains of ARTHUR GUINNESS.

late of ST JAMES GATE IN THE CITY.

and of BEAUMONT IN THE COUNTY OF DUBLIN ESQUIRE.

Who departed this life on 23rd of January A.D. 1803 aged 78 years He stopped reading, shaking his head, holding his anger in check. 'Next time I have a pint of Guinness it'll be to celebrate catching the sick bastard. And it won't be with his blood money. Come on, we need to find out where this grid reference is.'

The Assistant Commissioner placed a thick arm across the door. 'I'm sorry, Dr Jacobs, this is going to have to be a closed meeting. If you could wait outside, we'll call you if we need any advice.'

Jacobs did her best not to look offended and headed for a small sofa next to a coffee table, the day's papers laid out across it. As the door closed the AC's secretary gave her an apologetic smile.

The AC sat behind his desk, Bishop and McEvoy seated opposite. 'Tell me about the note,' he instructed, resting his giant hands on his stomach.

'It was left in Oughterard Cemetery next to Arthur Guinness' grave,' McEvoy replied. 'It lists the exact latitude and longitude of all seven murders. The last murder is due to take place on O'Connell Street at the spire.'

'Are you sure about that?'

'That's what the note says and I've had it double-checked. All the other references are perfect. He left us a list of every site.'

'So why didn't we break the code earlier?'

'Because we didn't have enough letters to break it and even if we did we wouldn't have been able to pinpoint the location until we'd got the most recent letters.'

The AC nodded and turned to look out of the window at the grey sky, a light drizzle flecking the windows. 'So what are you proposing to do?'

'I think we flood the area with hand-picked, plain clothes personnel. We wait until he turns up and we arrest him. There's the risk that he might kill his target but hopefully we can prevent it.'

'Hopefully?'

'I think it's a risk we have to take. He's giving us the perfect opportunity to catch him; we might not get one again. So far, we've had very little to go on. If he goes to ground it might take us months to pick up his scent again. May never pick it up.'

'What's your view, Tony?' the AC asked.

'I think it's a hell of a risk,' Bishop cautioned. 'If we leave O'Connell Street open and he manages to commit his murder they'll be hell to pay, even if we do catch the bastard. And if we don't catch him then we'll be hung out to dry. There'll be no hiding place and they'll be merciless. You've seen what they're like. Either way, the press will say we've been playing Russian roulette with people's lives. I think we close the whole area down; locked tight. We say there's been a security alert, whatever, it doesn't matter. If we do that, then we close off his opportunity to commit his last murder and finish his book. If he still turns up, then we stand a better chance of catching him.'

'If we shut O'Connell Street he's still going to kill someone, somewhere,' McEvoy countered. 'He's invested too much time and energy to simply walk away. He needs to finish his book. Whatever happens, I think he'll try and do that. If we seal off O'Connell Street, he'll have a contingency plan. He'll just murder some other poor fecker somewhere else in the city. He'll then tell the press that the O'Connell Street reference was a bluff, a stunt to misdirect our attention, and what's more they'll believe him.

'This whole thing's about ego, it's about outsmarting everyone and proving how clever he is. I think he will show up on O'Connell Street tomorrow and we should be there to meet him. Either way he's going to try and kill someone. I'm a hundred percent confident about that. We can be there to catch him or we can let him get away with it. The press are going to crucify us whatever we do. I think we just forget about them and concentrate on him. He's all that really matters.'

The AC looked back from the window at McEvoy and then up to the ceiling, bridging his fingers.

'Well, what do you think, Tony?'

'I still think it's a hell of a risk. We've no way of knowing that he's got a contingency plan. And we've no way of knowing how he intends to kill his last victim. He might not show up at all. He might have planted a bomb on a timer, blows up half the street and kills God knows how many. There'll be thousands of people out shopping, plus all the traffic.'

'He's not going to use a bomb,' McEvoy said firmly. 'Everything so far has been up close and personal strangling, battering, slashing, suffocating. He's not used a gun and he won't use a bomb. Unless he has specialist knowledge he'd have to source a bomb, and even if he did know how to make one he'd still has to get his hands on the materials explosives, detonators, timers. He's a loner and he wants no loose ends.

'We could, however, undertake a tactical bomb search this evening,' McEvoy suggested, his mind jumping ahead. 'The alert will warn a lot of people off, make the place a lot quieter than it would be otherwise. We could also partially shut the street down, for example, closing it to traffic. We could say there's emergency street work taking place a broken main or something. It doesn't matter what, as long as it looks genuine. The crew could be some of our team. If it's still open, even partially, I think he'll show.'

'Even if you're right about the up close and personal bit, we're still putting the public in the firing line,' Bishop countered. 'We're leaving ourselves wide open to allegations of serious misconduct.'

'We're leaving the public in the firing line even if we close O'Connell Street. If he wants to kill his last victim he'll just move his final attack to Grafton Street or the Powerscourt Centre or Jervis Street or the Ilac Centre or Connolly Station or Heuston Station, the list of potential targets is endless. Plus we're leaving him at large to kill again. And he will kill again. We all know that.'

'If we partially close O'Connell Street he'll know we're waiting for him,' Bishop reasoned.

'He knows we will be in any case. He left us a note telling us where each murder will take place. He's laid down a challenge and I think he'll show up as long as we don't shut the place down entirely. He's going to kill again whatever we do, this is our one clear chance to catch him.'

The room descended into silence. The AC placed his elbows on the desk, interlocked his fingers and drew them to his mouth, his gaze unfocused. After 20 seconds or so he said, 'I need to talk to the Commissioner and then probably the Minister for Justice. There's no way I'm making this kind of decision without sanction. He's got us caught between a rock and a hard place.' He paused. 'This conversation stays between the three of us, okay? And even if we do go ahead with an operation, it'll be limited personnel on a strict no-gossip basis. I don't want vigilantes or panic on the streets. Nobody's to know details of that location, especially the press. Nobody. Understand?'

There was an expectant air in the room, a feeling that they might be on the edge of a breakthrough. They all knew that McEvoy had been out to Oughterard Cemetery, that a note had been found.

'Right, okay, let's make a start,' McEvoy said, Jacobs standing next to him. 'Come on, let's quieten down.' He waited until the DIs and crime scene managers were hushed. 'I want to start with an introduction. This is Dr Kathy Jacobs. She's a criminal profiler and will be working with us to try and help focus our efforts. She's had a look through some of the case notes and will be working on the files in order to construct her profile. She's to get your full co-operation. Understood?'

Jacobs nodded at the faces staring at her and sat at a nearby desk.

'Right, as you're all aware, there was a sixth murder this morning. Shirley Hamilton, 53, a staff development trainer from Belfast. Jim, you got any updates?'

The room's occupants shifted on their seats and shared quizzical glances. They were expecting McEvoy to detail what had been found, to see how it might influence their investigations, not to simply run through all the enquiries.

'Not really,' Whelan answered. 'She was battered to death. No sign of him or the weapon.'

McEvoy sighed inwardly; getting information out of Whelan was next to impossible. He'd been working that site all day and all he could manage was three short sentences. 'How about you, Cheryl?'

'What we have's in the lab. And it's not much to be honest. We're working through it, but it's slow work. The whole place is flat out and there's a huge backlog from the other murders. It'll probably be days before it's all worked through.'

'Right, okay,' McEvoy said frustrated. 'Right, I know it's early, but has there been any progress with the five names that Dermot Brady gave us?'

'One of them was out of the country at the time of the first murder,' Johnny Cronin said, 'trying to catch the last of the snow in Italy apparently. The prison warden's dead. Road accident two years ago; drink driving. The wannabe politician has a cast iron alibi he was at a council meeting the night of Grainne Malone's murder. We haven't managed to track down the other two yet. I have a couple of people on it.'

'Okay, we need to make that a priority. If they don't come up with solid alibis put them under surveillance. Right then, let's work through the other murders. Barney, any progress with Laura Schmidt?'

'Nothing. We're still working through Glencree's lists and trying to eliminate possibles. We've been attempting to open a decent channel up into the North in order to put pressure on some of the groups up there to co-operate. Maybe Shirley Hamilton's death might help, I don't know. Everything else has run cold nothing from the questionnaires, the searches or appeals.'

'How about Peter Killick?'

'Nothing so far. We're still working through CCTV footage from every camera within quarter of a mile. We've got people out showing the photofit and we're working through all the staff and customer's statements. He disappeared the moment he stepped out of the bar door.'

'Anything from forensics?' he asked Hannah Fallon.

'We're at the back of the queue with Cheryl. There were hundreds of hair and fluid samples in that place; probably from hundreds of different people. It's going to take us an age to process them all. And I hope someone's got deep pockets because it's going to cost a fortune as well.'