On arrival, the tall blonde Scot who was heading the team ducked out of an interrogation room for a minute to shake hands. Strike and Robin knew that the police had brought two suspects in for questioning, although nobody had yet been charged.

“We spent the morning on hysterics and flat denial,” DCI Judy McMurran told them, “but I think we’ll have cracked her by the end of the day.”

“Any chance we could give them a little look, Judy?” asked her subordinate, DI George Layborn, who had met Strike and Robin at the door and brought them upstairs. He was a pudgy man who reminded Robin of the traffic policeman who had thought he was such a card, back on the hard shoulder where she’d had her panic attack.

“Go on, then,” said DCI McMurran, with a smile.

Layborn led Strike and Robin around a corner and through the first door on their right into a dark and cramped area, of which half one wall was a two-way mirror into an interrogation room.

Robin, who had only ever seen such spaces in films and on TV, was mesmerized. Kinvara Chiswell was sitting on one side of a desk, beside a thin-lipped solicitor in a pinstriped suit. White-faced, devoid of makeup, wearing a pale gray silk blouse so creased she might have slept in it, Kinvara was weeping into a tissue. Opposite her sat another detective inspector in a far cheaper suit than the solicitor’s. His expression was impassive.

As they watched, DCI McMurran re-entered the room and took the vacant chair beside her colleague. After what felt like a very long time, but was probably only a minute, DCI McMurran spoke.

“Still nothing to say about your night at the hotel, Mrs. Chiswell?”

“This is like a nightmare,” whispered Kinvara. “I can’t believe this is happening. I can’t believe I’m here.”

Her eyes were pink, swollen and apparently lashless now that she had wept her mascara away.

“Jasper killed himself,” she said tremulously. “He was depressed! Everyone will tell you so! The blackmail was eating away at him… have you talked to the Foreign Office yet? Even the idea that there might be photographs of that boy who was hanged—can’t you see how scared Jasper was? If that had come out—”

Her voice cracked.

“Where’s your evidence against me?” she demanded. “Where is it? Where?”

Her solicitor gave a dry little cough.

“To return,” said DCI McMurran, “to the subject of the hotel. Why do you think your husband called them, trying to ascertain—”

“It isn’t a crime to go to a hotel!” said Kinvara hysterically, and she turned to her solicitor, “This is ridiculous, Charles, how can they make a case against me because I went to a—”

“Mrs. Chiswell will answer any questions you’ve got about her birthday,” the solicitor told DCI McMurran, with what Robin thought was remarkable optimism, “but equally—”

The door of the observation room opened and hit Strike.

“No problem, we’ll shift,” Layborn told his colleague. “Come on, gang, we’ll go to the incident room. Got plenty more to show you.”

As they turned a second corner, they saw Eric Wardle walking towards them.

“Never thought I’d see the day,” he said, grinning as he shook Strike’s hand. “Actually invited in by the Met.”

“You staying, Wardle?” asked Layborn, who seemed faintly resentful at the prospect of another policeman sharing the guests he was keen to impress.

“Might as well,” said Wardle. “Find out what I’ve been assisting in, all these weeks.”

“Must’ve taken its toll,” said Strike, as they followed Layborn into the incident room, “passing on all that evidence we found.”

Wardle sniggered.

Used as she was to the cramped and slightly dilapidated offices in Denmark Street, Robin was fascinated to see the space that Scotland Yard devoted to the investigation into a high profile and suspicious death. A whiteboard on the wall carried a timeline for the killing. The adjacent wall bore a collage of photographs of the death scene and the corpse, the latter showing Chiswell freed from his plastic wrapping, so that his congested face appeared in awful close-up, with a livid scratch down one cheek, the cloudy eyes half open, the skin a dark, mottled purple.

Spotting her interest, Layborn showed her the toxicology reports and phone records that the police had used to build their case, then unlocked the large cupboard where physical evidence was bagged and tagged, including the cracked tube of lachesis pills, a grubby orange juice carton and Kinvara’s farewell letter to her husband. Seeing the note that Flick had stolen, and a printout of the photograph of “Mare Mourning” lying on a spare bed, both of which Robin knew had now become central to the police case, she experienced a rush of pride.

“Right then,” said DI Layborn, closing the cupboard and walking over to a computer monitor. “Time to see the little lady in action.”

He inserted a video disk in the nearest machine, beckoning Strike, Robin and Wardle closer.

The crowded forecourt of Paddington station was revealed, jerky black and white figures moving everywhere. The time and date showed in the upper left corner.

“There she is,” said Layborn, hitting “pause” and pointing a stubby figure at a woman. “See her?”

Even though blurred, the figure was recognizable as Kinvara. A bearded man had been caught in the frame, staring, probably because her coat hung open, revealing the clinging black dress she had worn to the Paralympian reception. Layborn pressed “play” again.

“Watch her, watch her—gives to the homeless—”

Kinvara had donated to a swaddled man holding a cup in a doorway.

“—watch her,” Layborn said unnecessarily, “straight up to the railway worker—pointless question—shows him her ticket… watch her, now… off to the platform, stops and asks another bloke a question, making sure she’s remembered every bloody step of the way, even if she’s not caught on camera… aaaand… onto the train.”

The picture twitched and changed. A train was pulling into the station at Swindon. Kinvara got off, talking to another woman.

“See?” said Layborn. “Still making damn sure people remember her, just in case. And—”

The picture changed again, to that of the car park at Swindon station.

“—there she is,” said Layborn, “car’s parked right near the camera, conveniently. In she gets and off she goes. Gets home, insists the stable girl stays overnight, sleeps in the next room, goes outside next morning to ride within sight of the girl… cast-iron alibi.

“Course, like you, we’d already come to the conclusion that if it was murder, it must have been a two-person job.”

“Because of the orange juice?” asked Robin.

“Mostly,” said Layborn. “If Chiswell” (he said the name as it was spelled) “had taken amitriptyline unknowingly, the most likely explanation was that he’d poured himself doctored juice out of a carton in the fridge, but the carton in the bin was undoctored and only had his prints on.”

“Easy to get his prints on small objects once he was dead, though,” said Strike. “Just press his hand onto them.”

“Exactly,” said Layborn, striding over the wall of photographs and pointing at a close-up of the pestle and mortar. “So we went back to this. The way Chiswell’s prints are positioned and the way the powdered residue was sitting there pointed to it being faked, which meant the doctored juice could have been fixed up hours in advance, by somebody who had a key, who knew which anti-depressants the wife was on, that Chiswell’s sense of taste and smell were impaired and that he always drank juice in the mornings. Then all they’d need to do is have the accomplice plant an undoctored juice carton in the bin with his dead handprint on, and take away the one with the amitriptyline residue in it.

“Well, who’s better positioned to know and do all of that, than the missus?” asked Layborn rhetorically. “But here she was, with her cast-iron alibi for time of death, seventy-odd miles away when he was gulping down anti-depressants. Not to mention she’

s left that letter, trying to give us a nice clean story: husband already facing bankruptcy and blackmail realizes his wife’s leaving him, which tips him over the edge, so he tops himself.

“But,” said Layborn, pointing at the enlarged picture of the dead Chiswell’s face, stripped of its plastic bag, revealing a deep red scrape on the cheek, “we didn’t like the look of that. We thought from the first that was suspicious. Amitriptyline in overdose can cause agitation as well as sleepiness. That mark looked as though somebody else forced the bag over his head.

“Then there was the open door. The last person in or out didn’t know there was a trick to closing it properly, so it didn’t look like Chiswell was the last person to touch it. Plus, the packaging on the pills being absent—that smelled wrong from the start. Why would Jasper Chiswell get rid of it?” asked Layborn. “Just a few little careless mistakes.”

“It nearly came off,” said Strike. “If only Chiswell had been put to sleep by the amitriptyline as intended, and if they’d thought the thing through right to the finest details—close the door properly, leave the pill packaging in situ—”

“But they didn’t,” said Layborn, “and she’s not smart enough on her own to talk herself out of this.”

“‘I can’t believe this is happening,’” Strike quoted. “She’s consistent. On Saturday night she told us ‘I didn’t think this would happen,’ ‘it didn’t seem real—’”

“Try that in court,” said Wardle quietly.

“Yeah, what were you expecting, love, when you crushed up a load of pills and put them in his orange juice?” said Layborn. “Guilty is as guilty does.”

“Amazing, the lies people can tell themselves when they’re drifting along in the wake of a stronger personality,” said Strike. “I’ll bet you a tenner that when McMurran finally breaks her, Kinvara’ll say they started off hoping Chiswell would kill himself, then trying to pressure him into doing it, and finally reached a point when there didn’t seem much difference between trying to push him into suicide, and putting the pills in his orange juice herself. I notice she’s still trying to push the gallows business as the reason he’d top himself.”

“That was very good work of yours, connecting the dots on the gallows,” admitted Layborn. “We were a bit behind you on that, but it explained a hell of a lot. This is highly confidential,” he added, taking a brown envelope off a nearby desk and tipping out a large photograph, “but we had this from the Foreign Office this morning. As you can see—”

Robin, who had gone to look, half-wished she hadn’t. What was there to be gained, really, from seeing the corpse of what seemed to be a teenage boy, whose eyes had been picked out by carrion birds, and hanging from a gallows in a rubble-strewn street? The boy’s dangling feet were bare. Somebody, Robin guessed, had stolen his trainers.

“The lorry containing the second pair of gallows was hijacked. Government never took delivery and Chiswell never got payment for them. This picture suggests they ended up being used by rebels for extrajudicial killings. This poor lad, Samuel Murape, was in the wrong place at the wrong time. British student, gap year, out there to visit family. It’s not particularly clear,” Layborn said, “but see there, just behind his foot—”

“Yeah, that could be the mark of the white horse,” said Strike.

Robin’s mobile, which was switched to silent, vibrated in her pocket. She was waiting for an important call, but it was only a text from an unknown number.

I know you’ve blocked my phone, but I need to meet you. An urgent situation’s come up and it’s to your advantage as much as mine to sort it out. Matt

“It’s nothing,” Robin told Strike, returning the mobile to her pocket.

This was the third message Matthew had left that day.

Urgent situation, my arse.

Tom had probably found out that his fiancée and his good friend had been sleeping together. Maybe Tom was threatening to call Robin, or drop in on the office in Denmark Street, to find out how much she knew. If Matthew thought that constituted an “urgent situation” to Robin, who was currently standing beside multiple pictures of a drugged and suffocated government minister, he was wrong. With an effort, she refocused on the conversation in the incident room.

“… the necklace business,” Layborn was saying to Strike. “Far more convincing story than the one he told us. All that guff about wanting to stop her hurting herself.”

“It was Robin who got him to change his story, not me,” said Strike.

“Ah—well, good work,” Layborn said to Robin, with a hint of patronage. “I thought he was an oily little bastard when I took his initial statement. Cocky. Just out of jail, and all. No bloody remorse for running over that poor woman.”

“How are you getting on with Francesca?” Strike asked. “The girl from the gallery?”

“We managed to get hold of the father in Sri Lanka and he’s not happy. Being quite obstructive, actually,” said Layborn. “He’s trying to buy time to get her lawyered up. Bloody inconvenient, the whole family being abroad. I had to get tough with him over the phone. I can understand why he doesn’t want it all coming out in court, but too bad. Gives you a real insight into the mindset of the upper classes, eh, case like this? One rule for them…”

“On that subject,” said Strike, “I assume you’ve spoken to Aamir Mallik?”

“Yeah, we found him exactly where your boy—Hutchins, is it?—said he was. At his sister’s. He’s got a new job—”

“Oh, I’m glad,” said Robin inadvertently.

“—and he wasn’t overjoyed to have us turning up at first, but he ended up being very frank and helpful. Said he found that disturbed lad—Billy, is it?—on the street, wanting to see his boss, shouting about a dead child, strangled and buried on Chiswell’s land. Took him home with the idea of getting him to hospital, but he asked Geraint Winn’s advice first. Winn was furious. Told him on no account to call an ambulance.”

“Did he, now?” said Strike, frowning.

“From what Mallik’s told us, Winn was worried association with Billy’s story would taint his own credibility. He didn’t want the waters muddied by a psychotic tramp. Blew up at Mallik for taking him into a house belonging to the Winns, told him to turf him out on the street again. Trouble was—”

“Billy wouldn’t go,” said Strike.

“Exactly. Mallik says he was clearly out of his mind, thought he was being held against his will. Curled up in the bathroom most of the time. Anyway,” Layborn took a deep breath, “Mallik’s had enough of covering up for the Winns. He’s confirmed that Winn wasn’t with him on the morning of Chiswell’s death. Winn told Mallik afterwards, when he put pressure on Mallik to lie, he’d had an urgent phone call at 6 a.m. that day, which is why he left the marital home early.”

“And you’ve traced that call?” said Strike.

Layborn picked up the printout of phone records, rifled through them, then handed a couple of marked pages to Strike.

“Here you go. Burner phones,” he said. “We’ve got three different numbers so far. There were probably more. Used once, never used again, untraceable except for the single instance we got on record. Months in the planning.

“A single-use phone was used to contact Winn that morning, and two more were used to call Kinvara Chiswell on separate occasions during the previous weeks. She ‘can’t remember’ who called her, but both times—see there?—she talked to whoever it was for over an hour.”

“What’s Winn got to say for himself?” asked Strike.

“Closed up like an oyster,” said Layborn. “We’re working on him, don’t worry. There are porn stars who’ve been fucked fewer different ways than Geraint W—sorry, love,” he said, grinning, to Robin, who found the apology more offensive than anything Layborn had said. “But you take my point. He might as well tell us everything now. He’s screwed every which w—well,” he said, floundering once more. “What interests me,” he started up again, “is how much the wife knew. Strange wo

man.”

“In what way?” asked Robin.

“Oh, you know. I think she plays on this a bit,” said Layborn, with a vague gesture towards his eyes. “Very hard to believe she didn’t know what he was up to.”

“Speaking of people not knowing what their other halves are up to,” interposed Strike, who thought he detected a martial glint in Robin’s eye, “how’s it going with our friend Flick?”

“Ah, we’re making very good progress there,” said Layborn. “The parents have been helpful in her case. They’re both lawyers and they’ve been urging her to cooperate. She’s admitted she was Chiswell’s cleaner, that she stole the note and took receipt of the crate of champagne right before Chiswell told her he couldn’t afford her anymore. Says she put it in a cupboard in the kitchen.”

“Who delivered it?”

“She can’t remember. We’ll find out. Courier service, I shouldn’t wonder, booked on another burner phone.”

“And the credit card?”

“That was another good spot of yours,” admitted Layborn. “We didn’t know a credit card had gone missing. We got details through from the bank this morning. The same day Flick’s flatmate realized the card was gone, somebody charged a crate of champagne and bought a hundred quid’s worth of stuff on Amazon, all to be sent to an address in Maida Vale. Nobody took delivery, so it was returned to the depot where it was picked up that afternoon by someone who had the failed delivery notice. We’re trying to locate the staff who can identify the person who collected it and we’re getting a breakdown on what was bought on Amazon, but my money’s on helium, tubing and latex gloves.

“This was all planned months in advance. Months.”

“And that?” Strike asked, pointing to the photocopy of the note in Chiswell’s handwriting, which was lying on the side in its polythene bag. “Has she told you why she nicked it yet?”