Amalfi Casino and Hotel Resort, Las Vegas

17th March – 11.22 p.m.

It was funny how people conditioned themselves to only ever see what they wanted to, Foster mused. Ask anyone who wears a watch with Roman numerals how the number four is written on it and they’ll say IV. All those years that they’ve been looking at it, checking the time, the numbers only a few inches from their stupid dumb-ass faces, and they’ve never actually noticed that it’s IIII. That it’s always IIII on a watch, because IV would be too easily confused with VI. That their brains have tricked them into seeing what they expect to, or rather not seeing what they should. It was pathetic really.

Like tonight. The security detail at the staff entrance had barely glanced at his badly fitting uniform and tampered badge before waving him through. He looked the part, so why see something that you’ve convinced yourself isn’t there? That’s why the beard had had to go in the end; that might have been the one thing that could have triggered a response.

He, on the other hand, had immediately picked out the FBI agents, uncomfortable in their civilian clothes as they loitered near the entrance, or perched unconvincingly in front of the slot machines. It was the half-hearted way they were feeding the money into the machine that was the killer tell – either you played the slots, or they played you.

He stopped next to an anonymous-looking red door. How many people had walked past it, he wondered, without ever asking themselves why, out of all the doors that lined this service corridor, this was the only one that warranted two locks. Without ever asking themselves what might possibly lie behind it that demanded the extra security. But then, that’s what he’d noticed in civilians: a lack of basic human curiosity, a slavish, unquestioning acceptance of a life dropped into their lap like a TV dinner.

Quickly picking the locks, he opened the door on to a dimly lit stairwell that he slipped into, wedging a fire extinguisher between the base of the door and the bottom step of the metal staircase to stop anyone coming in after him. The staircase led up several flights to the observation deck – a series of cramped, interconnecting gantries hidden in the ceiling void that stretched over the entire casino floor.

Although in theory these were to allow maintenance staff to invisibly service the casino’s complex lighting grid and vast network of A/C ducts, the careful positioning of two-way mirrors and air vents also allowed casino security to spy on people without being seen. Dealers watching the gamblers, boxmen watching the dealers, supervisors watching the boxmen, pit bosses watching the supervisors, shift managers watching the pit bosses…the entire set-up functioned on the assumption that everyone was on the make and on the take.

Not that the deck was used as often as it used to be – video cameras and advances in biometric technology that could flag-up suspicious changes in body heat and pupil dilation had seen to that. But Kezman was famously old-school and had insisted on having it there anyway, both as a low-tech back-up, and because he knew that sometimes you needed to get up there and sniff the floor to get a feeling for where the trouble was brewing.

As Foster had expected, the gantries were empty. He took up his position, removed the towel from his back-pack, and unrolled it. Piece by piece he began to reassemble his rifle, the parts sliding into place with a satisfying click echoed by the sound of the roulette ball skipping on the wheel below. With the infrared sight fitted he hesitated momentarily, toying with the suppressor before slipping it into his top pocket like a good cigar he was saving for the right moment.

No suppressor. Not tonight. He wanted everyone to hear the shot, to be paralysed by its angry roar, and then to run. To run screaming.

The Pantheon, Rome

18th March – 7.41 a.m.

Allegra was sheltering in the portico, grateful for the coffee Salvatore had conjured up for her and for the fresh air – there had been a strange, curdled atmosphere inside that she had been glad to escape.

The storm had now tethered itself directly overhead, rain lashing the square, lightning cleaving the stygian sky only for the clouds to crash thunderously back together. But it was the more powerful storm brewing on the other side of the barricades that worried her now. Rising out of the warm waters of political scandal and feeding on the lurid details of these murders, it would quickly spin out of control, blowing them violently towards the rocks until either the media lost interest or they had all been dashed into pieces, whichever came sooner. She wondered if Gallo’s men all knew this, and whether what she could sense inside, what she could almost taste, was their fearful anticipation of the hurricane that lay ahead.

‘So it’s the same coin?’ Gallo had materialised at her side, lighting a cigarette.

‘I thought you’d given up?’

‘So did I.’

She was reassured that she wasn’t the only one feeling the pressure.

‘It’s the same.’ She nodded, not bothering to repeat that it wasn’t a coin but a lead disc.

‘So it’s the same killer?’

‘Are you asking me or telling me?’

‘I’m asking.’ As earlier, the hint of a smile was playing around his lips, as if she somehow amused him.

‘There are some obvious similarities,’ she began hesitantly, surprised that Gallo even cared what she thought. ‘The lead discs. The proximity of the two murder scenes. The pagan temples. The connection to Caesar. But…’

‘But what?’

‘It’s…the way they were killed. I’m not a profiler, but there’s no consistency between the two murders. They look different. They feel different.’

‘I agree. Two murders. Two killers.’ Gallo held up photographs of the two crime scenes side by side as if to prove his point.

Allegra glanced at the photos and jumped. There was something in the crime scenes, something she’d not noticed before, but which, when framed within the photographs’ white borders, was now glaringly obvious.

‘Where’s your car?’

‘Over there -’ He pointed out a dark blue BMW.

‘Come on!’ She stepped out into the rain, then turned and motioned impatiently at him to follow when she realised he hadn’t moved.

‘Where to?’

‘The Palazzo Barberini,’ she called back, her hair darkening. ‘There’s something there you need to see.’

A few moments later, Gallo gunned out of the square down the Via del Seminario, the Carabinieri clearing a path for him through the crowd, Allegra shielding her face as the photographers and TV crews pressed their lenses up against their windows. As soon as they were clear, he accelerated through the Piazza San Ignacio and out on to the busy Via del Corso, his siren blazing as he carved his way through the rush-hour traffic. Reaching the Via del Tritone he turned right, racing down to where the palazzo loomed imposingly over the Piazza Barberini and then cutting up a side street to the main entrance at the top of the hill. The drive was chained off, although the museum was clearly open, those foreign tourists still able to swallow the euro’s inexorable climb over the past few months already filtering through the gates.

‘Damn these peasants,’ Gallo muttered, leaning on his horn, until a guard appeared and let them through.

They lurched forward, the gravel spitting out from under their tyres as they shot round to the far side of the fountain.

‘First floor,’ Allegra called as she jumped out and headed through the arched entrance, not pausing on this occasion to admire the monumental Bernini staircase that led up to the Galleria Nazionale d’Arte Antica, the museum that now occupied this former papal residence.