It seemed to work. A minute or two passed and then the old man’s eyes no longer looked quite so terrified. Instead Lorimer waved a shaking hand at some papers lying on his bedside table. Forrester got up and walked to the table and picked up the documents. It was a sheaf of handwritten notes.

‘Yours?’

Lorimer nodded. Keeping his lips firmly shut.

‘Descriptions of the attackers?

He nodded again.

‘Thank you very much, Mr Lorimer.’ Forrester reached out and patted him on the shoulder, feeling self-conscious as he did so. The man really looked as if he was about to cry.

Pocketing the papers, Forrester left the room as quickly as he could. Out and down the steps and through the swing doors. When he reached the rainy late spring air of the leafy Embankment he breathed deeply, and in relief. The atmosphere of terror in the room, in the man’s staring eyes, had been all too intense.

Walking briskly down and across the River Thames, with the Houses of Parliament yellow and Gothic on his left, Forrester read the scrawled notes.

David Lorimer was a caretaker. At the Benjamin Franklin Museum. He was sixty-four. Nearing retirement. He lived alone in a flat at the top of the museum. The previous night he had woken at about 4 a.m. to the muffled crash of broken glass downstairs. His flat was in a converted attic and he’d had to descend all the way to the cellar. There he’d found five or six unknown men, apparently young, and wearing ski-masks or balaclavas. The men had broken in, quite expertly, and they were digging up the basement floor. One of them had a ‘posh voice’.

And that was pretty much all Lorimer’s notes said. During the attack a car alarm had gone off, for some reason, probably sheer and miraculous coincidence-just as the men were carving Lorimer’s neck and chest, and so the men had fled. The caretaker was lucky to be alive. If the young lad, Alan Greening, hadn’t wandered in and found him he would have bled to death.

Forrester’s mind was full of speculation. Turning right on the Strand, he headed down the quiet Georgian side street to the museum, the Benjamin Franklin House. The house was roped off with blue and white plastic tape. Two police cars were parked outside, a uniformed constable stood by the door, and a couple of obvious journalists with recorders were sheltering under a nearby office block awning, with cups of takeaway coffee.

One of them stepped forward as Forrester approached. ‘Detective, is it true the victim had his tongue cut out?’

Forrester turned and smiled blandly and said nothing.

The journalist, young, female and pretty, tried again. ‘Was it some kind of neo-Nazi thing?’

This made Forrester pause. He turned and looked at the girl. ‘Press conference is tomorrow.’ This was a lie, but it would do. Turning back to the house, he ducked under the tape and flashed his badge. The uniformed constable opened the door and Forrester immediately caught the piercing, chemical smell of Forensics at work. Fuming for fingerprints. Quasaring the place. Silicon gel and superglue. Stepping to the end of the noble Georgian hall with its portraits of Benjamin Franklin, Forrester took the narrow stairway to the basement.

The cellar was a scene of activity. Two Forensics girls in green paper nonce suits and masks were working at one end. The bloodstains on the floor were vivid, sticky and dark. Detective Sergeant Boijer waved from the other side of the room. Forrester smiled back.

‘They were digging in here,’ said DS Boijer. Forrester noted that Boijer’s blond hair was newly cut, and expensively so.

‘What were they digging for?’

DS Boijer shrugged. ‘Search me, sir.’ He waved a hand across the ripped-up flagstones. ‘But they had a good old hunt. Must have taken them a couple of hours to shift all that shit, and get that deep.’

Forrester bent to assess the disturbed soil, the deep, damp hole in the earth.

Boijer chatted away behind him: ‘Did you see the caretaker?’

‘Yep. Poor bastard.’

‘The doctor told me they were trying to kill him. Slowly.’

Forrester replied without looking around. ‘I think they were bleeding him to death. If the car alarm hadn’t gone off, and if he hadn’t lucked out with that lad arriving he would have died of blood loss.’

Boijer nodded.

Forrester stood up. ‘So it’s attempted murder. Better speak to Aldridge. He’ll want an SIO, and the rest. Set up an incident room.’

‘And the scars on his chest?’

‘Sorry?’

Forrester turned. Boijer was wincing, and holding a photo. ‘You haven’t seen this?’ He handed the photo over. ‘The doctor took a photo of the scars on the guy’s chest. He emailed it to the station this morning, didn’t get a chance to show you.’

Forrester looked. The caretaker’s white chest was exposed to the camera, soft and vulnerable. Bloodily carved in the skin was a Star of David. Unmistakable. The flesh was crudely ripped, but the sign was clearly legible. Two juxtaposed triangles. A Jewish Star of David. Carved into living flesh and blood.

‘So these are the carvings, the new ones they mentioned in the article?’

‘Ja.’

Rob was in the middle of the dig, next to Breitner. The two of them were standing at the side of a pit, looking down at a circle of tall, T-shaped stones within the sunken enclosure. These were the megaliths. All around them the dig was proceeding with alacrity: Turkish workers were brushing and shovelling earth, shinning down ladders, trundling barrows of rubble along duckboards. The sun was hot.

The carvings were strange-and yet familiar, because Rob had seen them in the newspaper photos. There was a stone carved with lions, and a few weathered birds; maybe ducks. On the next stone was something that looked like a scorpion. About half the megaliths had similar carvings, many of them seriously eroded, others not. Rob took some shots with his cameraphone then scribbled a few impressions in his notebook, drawing the strange T-shape of the megaliths as best he could.

‘But,’ said Breitner, ‘that of course is not everything. Komm.’

They walked along the side of the pit to another sunken area. Three more ochre pillars stood in this enclosure, surrounded by a mudbrick wall. Traces of what looked like tiling glinted on the floor between the pillars. A blonde German girl said Guten Tag to Rob as she pushed past carrying a small clear plastic bag full of tiny flints.

‘We have many students here from Heidelberg.’

‘And the other workers?’

‘All Kurdish.’ Breitner’s twinkling eyes clouded for a moment behind his spectacles. ‘I also have other experts here of course, paleobotanists and two or three other specialists.’ He took out a handkerchief and wiped perspiration from his bald head. ‘And this is Christine…’

Rob turned. Approaching him from the direction of the tented headquarters was a petite but determined figure in khaki trousers and a remarkably clean white shirt. Everybody else in the dig was smothered with the ubiquitous beige dust of Gobekli Tepe’s exhausted-looking hillocks. But not this archaeologist. Rob felt himself go tense-as he always did when he was introduced to an attractive young woman.

‘Christine Meyer. My skeleton woman!’

The small, dark-haired woman extended a hand: ‘Osteoarchaeologist. I do the biological anthropology. The human remains and so forth. Not that we have found anything of that nature yet.’

Rob detected a French accent. As if he guessed Rob’s thoughts, Breitner interrupted. ‘Christine was at Cambridge under Isobel Previn, however she is from Paris so we are very international here…’

‘I’m French, yes. But I lived in England for many years.’

Rob smiled: ‘I’m Rob Luttrell-we share a back-ground! I mean I’m American. But I’ve been living in London since I was ten.’