Eventually he broke the silence. “Tell me about Derek Stanley.”

“Can you be more precise?”

“What does he do for a living? What does he spend his time doing when he’s not working? Where does he live? What I’m trying to work out is where he might be now. He’s parked his car at the Fox. He’s made his way to the Cedars on foot. Let’s suppose that somehow he has drugged both Becca Baines and Doug Mullen. Mullen’s car is missing. I am guessing Stanley wants us to assume what we did assume, namely that it was Mullen that drugged Becca — and Chris and Janice too of course — and that now Mullen has done a runner. So what is Stanley going to do next?”

Dorkin paused briefly. It wasn’t a proper question, more a case of him thinking out loud, but Rose Wilby answered it anyway. She spoke quietly. “He’s going to kill Doug and bury him somewhere he won’t be found . . .”

“Or maybe make it look like suicide,” Dorkin said. “If he did that, he wouldn’t have to worry about disposing of the car. It’s harder to make a car disappear without trace than a body.”

Rose began to cry. Silent sobs shook her body.

“We can save Mullen if we can find him.” Dorkin held out a hope that he didn’t feel. “Time is against us, but he’s only been missing an hour or two. So I need you to think. The chances are that they are not far away. Stanley will know that if he drives Mullen’s car too far, he is at risk of being caught on camera and picked up by us. We will be looking for Mullen’s car because we’ll be looking for Mullen. Unless Stanley intends to disappear himself, he needs to return for his car so he can drive back home as if nothing had happened. So what I want you to tell me is did Stanley have any favourite places he used to go? A wood maybe. A cottage in the countryside.” Dorkin dribbled to a halt. He had run out of suggestions. There was plenty of woodland up here on Boars Hill, he told himself, but there were plenty of big houses too. It was hardly an ideal place for Stanley to hold and kill Mullen. But if they were going to lay on a search, they had to start somewhere — assuming, of course, that he was given the manpower to do so.

Rose Wilby stood up very suddenly and clapped her hands together. “Of course! Savernake Forest. He goes there two or three times a year.”

Dorkin looked at her. His first reaction was negative: Savernake Forest was a heck of a long way away if Stanley was intending to make his way back to Boars Hill to collect his own car.

“You remember the Hungerford massacre?” Rose pinioned Dorkin with her intense gaze. “Michael Ryan ran amok in Hungerford. But the first killing took place in Savernake Forest. Stanley’s sister was living in Hungerford at the time. She was injured by a shot through her window. Nothing critical, but she was so traumatised that she committed suicide a year later. Anyway Derek goes back there every anniversary of her death. It’s like a pilgrimage. He goes other times too. Sometimes he camps out in the woods.”

“So he’ll know it really well.”

“I would have thought so.”

Dorkin stood up. “That’s where we’ll start then. Unless the team have turned up anything else that points towards another direction.”

They strode side by side back to the little swing gate, across the road and along the pavement to the Cedars. Not for the first time that day, a red-faced Fargo came hurrying down the drive. This time there was a grin on his face. “Mullen’s car, Guv. The guys have got a fix on it. It went down the A34 and then west along the M4. We’ve got only one sighting on the M4, so they may have exited before they got as far as Swindon.”

“Get out of those overalls,” Dorkin snapped. “They’ve gone to Savernake Forest. And we need to organise some back-up.”

Fargo stared at him. “Savernake?”

“Don’t stand there gawping, Sergeant. We’ve got a killer to catch.”

* * *

Mullen was buried deep underground. He had to be. It was so silent and so dark. He began to feel panic crawling over him, like a giant spider. Oh God! He tried to thrust his head upwards, as far as his bonds would allow, dreading the moment when his head made contact with the lid of the coffin and confirmed his worst fears. Nothing. He tried again, straining even harder to stretch his neck that bit further, but again all he encountered was air. Stale air, but air nevertheless. Air! If he was entombed in a coffin underground, there wouldn’t be any air worth speaking of and he would surely have used it all up by now. He would be dead, whereas he most certainly wasn’t. He felt an absurd sense of relief, absurd because he knew with certainty that his chances of getting out were virtually nil. He lay back and listened to his own breathing as it returned to normal after his exertions.

He heard another noise. It was a mechanical noise, a scraping sound, a key in a lock he thought. There was another noise, of an unoiled door squeaking open. A light flashed into his face. He shut his eyes and tried to turn away.

“Awake at last.”

Mullen said nothing, largely because he couldn’t. There was a gag digging into his mouth.

“Thought I had overdone it. Thought I had lost you. The problem was I didn’t have a clue how much you’d drink, so I had to put plenty of rohypnol in the bottle.”

Stanley giggled. “It was bloody neat the way you both drank it. Couldn’t have worked out better! You leave her dosed up on the floor and you disappear. A day or two later a walker finds you here in the woods, hanging from a tree. Your last text message is a single word: ‘Sorry.’ But it’s a word that says it all: sorry for Becca, sorry for Chris, sorry for Janice. As far as the police are concerned, it’s case closed.”

Stanley moved closer to him and began to loosen the ropes that were holding Mullen captive. “I’ve got a Taser, so one wrong move and I let you have it in the neck.”

Mullen couldn’t make any moves, let alone a wrong one. When Stanley told him to get up, his ankles were still hobbled and his hands tied behind his back. He would have to bide his time. There would come a moment when he could make a move. He had to be ready for that split-second opportunity. He had to believe that his chance would come. And yet Stanley’s professionalism told him differently. There were no real clues as to where he had been held all this time — nor did Mullen have any idea how long he had been there. All he knew was that he was aching worse than he could ever recall aching before.

Stanley had put a noose round his neck and was leading him by the rope through a door. “If you try anything stupid, I’ll burn you alive. Got it? So it’s your choice. What sort of death do you want?”

It was dark outside. Not pitch dark, but dark enough. Half-nine or ten Mullen reckoned. So not much chance of running into any dog walkers. He was on his own.

They stopped after Mullen had shuffled maybe a hundred metres. Stanley began to wrap the rope around the branch of a tree. Mullen struggled to understand at first. How could Stanley hang him from there? And then he noticed through the darkness what was on the other side of the tree. Nothing. Empty space. The tree was on the edge of a cliff. Not a Cornish-style coastal cliff, but there was enough of a drop for what Stanley was planning. Perhaps twenty metres. After that there would be only oblivion.

“Do you know why I did it?” Stanley seemed to want an answer. He stood in front of Mullen, keeping his distance, and demanded a response. “Well?”

Mullen thought he knew, but he shook his head. It was a case of anything to delay the end, to gain a bit of time. If Stanley was busy talking, he might let his guard down and make a mistake. If Mullen could get him close enough, maybe he could head-butt him — knock him down and kick him over the edge, though how easy it would be to kick with two feet bound close together and his hands tied behind his back was something Mullen tried not to think about too deeply.