He did not bother warning her this time or issuing ground rules that he guessed she would break anyway. He was rather less cautious about this interview than he had been about the one in Wakefield Prison, on top of which he now thought she’d probably had a point the night before. He might well get more out of Donna Langford with Anna along for the ride.

Presuming there was anything to get.

They didn’t talk much in the car. Thorne content to listen to the radio and Anna appearing to get the message. Waiting to cross the Holloway Road, Thorne slipped a CD into the player; a vintage bluegrass compilation. Lester Flatt and Earl Scruggs, the Louvin Brothers, Bill Monroe . . .

‘Oh, I love this sort of stuff,’ Anna said.

Thorne nudged the volume up as he accelerated away from the lights.

‘My dad used to have loads of these records.’

He glanced across and was pleased to see that she did not appear to be taking the piss; nodding her head in time to the music and smacking out the rhythm on her knees. She had made all the right noises when she had first seen the BMW, too; something Thorne was not accustomed to. Certainly not from work colleagues, most of whom delighted in describing the 1975, pulsar-yellow CSi as the ‘rusty banana’ or a ‘puke-coloured death-trap’. Anna told Thorne she thought it was ‘cool’. He told her she had very good taste, but couldn’t help wondering if she had held secret meetings with Holland or Hendricks, and had been comprehensively briefed on the best ways to wind him up.

‘My mum hates it, though,’ Anna said, smiling. She was still tapping along to the beat of the upright bass, the scratchy melody of the fiddle, and the syncopation, so delicately picked out on the resonator guitar.

‘This Weary Heart’ by the Stanley Brothers, honey-sweet and hell-dark, as the car turned off the Seven Sisters Road and slowed.

‘Most people do,’ Thorne said. ‘I think it’s one of the reasons I like it so much.’

Thorne and Anna exchanged a look as Donna marched past them down the path.

‘It’s a nice day. Let’s go to the park.’

The day, though bright and sunny, was hardly warm, while the park, a five-minute walk from Donna’s block, turned out to be a scrubby patch of green and brown no bigger than a couple of tennis courts. There was a pair of rusted swings and a set of goalposts without a net. A fire had scorched what might once have been a penalty area, and there was a collection of discarded cans and bottles scattered among the long grass behind.

The three of them squeezed on to a metal bench.

‘What was your first thought?’ Thorne asked. ‘Back when you saw that first picture of Alan.’

A few leaves skittered half-heartedly at their feet, and for the few seconds before Donna answered they all watched as a battered Nissan Micra raced down the small road that ran behind the goalposts.

‘I thought it was typical,’ Donna said, laughing. ‘Once I’d got over the shock, I mean. I started wondering why I hadn’t thought he was alive before. Why I ever thought I’d actually managed to get rid of him.’

‘Why “typical”?’

‘Alan never did anything by halves,’ she said. ‘He planned things out, thought them through, you know?’

‘So, this is all part of a plan?’ Anna asked. ‘The photos . . .’

‘Christ, I don’t know.’ Donna suddenly looked very weary as she lit a cigarette. ‘He used to tell this story,’ she said, ‘when he’d had a drink.’ She turned to Thorne, rubbed her belly through her thick coat. ‘Remember I told you about that scar he’s got, where he was knifed?’

Thorne nodded.

‘He’d bang on about how that only happened because he hadn’t thought things through properly. Because he hadn’t thought about the details. Basically, he was a cocky sod and he hadn’t reckoned on the other bloke carrying a knife. But he always said it taught him an important lesson. After that he became obsessed with planning stuff out, working through every eventuality.’ She sat back and screwed up her face, against the cold or an unpleasant memory. ‘However vicious business got, however mental some of it seemed, it was all . . . thought through, you know?’ She looked at Anna. ‘My husband never did a spontaneous thing in his life, love. So, yeah, I reckon he knows exactly what he’s doing.’

‘Why did you want him dead?’ Anna asked.

Donna let out a long, slow breath, threw a half-smile at Thorne.

‘It’s a reasonable question,’ he said.

It was also one Thorne had never asked, not to Donna’s face at least. As with so many cases, once he had got his result, in the form of Donna Langford’s confession, he had moved on to something else. There had been speculation about her motive, of course, not least in the Sunday People and the News of the World. But with a conviction more or less in the bag, Thorne had had neither the time nor the inclination to care a great deal about the ‘Why?’ Donna had not spoken in her own defence at the trial, her counsel fearing that she might come across as somewhat hard-faced and spoiled. Instead, her brief had spoken passionately about ‘years of mental torment and domestic abuse’. In the end, though, the jury had been unconvinced.

Such provocation, the prosecution had countered at the time, might understandably lead victims to lash out with knives and hammers, or, at a push, to slip rat poison into the old man’s shepherd’s pie. But calmly planning and paying for a gangland-style execution was a very different matter.

‘Alan was spontaneous enough when it came to using his fists,’ Donna said. ‘But even then he was usually smart enough to avoid hitting me where it would show.’ She had been staring at her feet, but now glanced up towards Anna. ‘I didn’t like what it was doing to Ellie. What he might do to her.’ She shook her head, as though correcting herself. ‘I never saw him hit her, but I was starting to think it was on the cards, and there was no way I was going to let that happen.’

Anna placed a hand on Donna’s arm.

‘So, it wasn’t about the money, then?’ Thorne said. He saw the look from Anna but stared right back, hoping she would get the message.

‘Look, I’m not going to deny that I thought I’d be all right when Alan was dead. That I thought I’d be comfortable.’ Donna stared across the park. By now, the Micra was stationary and two young men, two kids, were leaning against it, smoking and laughing. ‘That wasn’t the reason I wanted him gone, though, I swear to you. I had money when I was with him and I was miserable as sin.’ She shrugged. ‘I wasn’t remotely surprised that there was nothing left, either. I always thought he might be squirrelling it away overseas, somewhere the taxman couldn’t find it. Now I know he’s still alive, I’m damn well sure that’s what he did. One more thing he was planning for.’

‘Why the contract killer, though?’ Thorne remembered the smell of cooked meat in the forest clearing, and the questions the prosecution had put to the jury during the trial. The same questions that were posed in a dozen magazine articles and a particularly salacious edition of London Tonight. ‘Why bother with Paul Monahan? Why not just take a knife to him or batter him while he was asleep?’

Donna nodded, like they were fair questions. ‘Of course, I thought about all those things,’ she said. ‘All my options. In the end, though, I was just terrified that I wouldn’t hit him hard enough. That I wouldn’t stab him in the right place, wouldn’t get the dosage quite right, whatever. You wouldn’t want to be the person who tried to murder him and saw him survive.’

‘I imagine he wouldn’t have been too thrilled,’ Thorne said.

‘The way I chose to do it, by paying someone to do it for me, felt like the safest bet.’ She smiled, genuine enjoyment in it. ‘Alan wasn’t the only one who was concerned about details. Eventualities.’

Thorne glanced across and caught another look from Anna. There was enjoyment in her smile, too.

‘Monahan’s dead,’ Thorne said. ‘You should probably know that.’

Donna blinked three or four times, her face suddenly pale. She stared at Thorne for a few seconds, then looked to Anna. ‘When?’

‘Day before yesterday,’ Anna said. ‘He was stabbed in his cell.’

Donna took another moment, then shrugged. ‘Well, I’m not going to pretend I give a monkey’s.’

‘I wouldn’t expect you to,’ Thorne said.

They watched as a man came towards them walking a Jack Russell. He stopped a few feet away and waited, staring blithely into the distance while the dog curled out a good-sized turd in the middle of the path. Then he carried on walking.

As he passed the bench, Anna said, ‘You should pick that up.’

The man turned, yanked his dog closer and told her to go fuck herself.

Thorne stood up and stepped across. ‘That’s not very polite.’

The man sighed and tried to walk past, but Thorne moved sideways and pushed the flat of his hand into his chest. The dog was jumping and scrabbling at Thorne’s knees as he reached into his pocket and pulled out his warrant card.

‘Shit,’ the man said.

‘Now.’ Thorne held his ID inches from the man’s face. ‘Pick it up.’

‘I haven’t got a bag.’

‘Use your hands.’

‘What?’

‘It’s all right.’ Anna stood up and took a crumpled wad of tissues from her pocket. She leaned across and handed them over. The man dragged his dog back along the path, picked up its waste, then walked quickly away in the opposite direction.

Anna watched until he was out of sight. Muttered, ‘Arsehole.’

Thorne was still breathing heavily a few minutes later when the three of them began walking back towards Donna’s flat. Donna nodded over her shoulder towards Anna, who was a step or two behind them. ‘Looks like I picked the right girl for the job, doesn’t it?’ she said.

At the end of her path, Donna reached into her pocket and produced a brown envelope. ‘The latest photo. London postmark, same as before.’

Thorne took out the photo, not caring about how it was handled. The other photographs had gone to the FSS lab the day before, and he reckoned if there were any fingerprints to be had, they were as likely to be found on those as they were on this one. He would send over the envelope, though. It would not be the first time DNA had been extracted from the back of a stamp.

The photo was from the same set as the others. Sun, sea, the usual.

‘Why do you think he’s doing this?’ Thorne asked.

‘Revenge,’ Donna said. ‘It’s not complicated. What I said before, about not wanting Alan to survive and know that I’d tried to kill him? Well, that’s what’s happened, except that it’s taken him ten years to do something about it.’ She wrapped her anorak tight around her chest. ‘To take Ellie.’

‘So, why now?’ Anna asked.

‘It’s the perfect time,’ Thorne said. He remembered a case from a year or two earlier. A man whose girlfriend and child had been murdered just before his release from prison. It was as cold and brutal an act of revenge as Thorne had ever encountered, and it had gone on to cost many more lives.

Donna nodded. ‘Couldn’t be better, could it? He takes her just before I’m due to come out, when all I’m thinking about is being with her again.’

‘You think he planned that, too?’ Anna asked.

‘Oh yeah.’

‘Ten years ago?’

‘You don’t know him,’ Donna said. Her voice dropped away as the anger took hold. ‘First he . . . takes her. Then he sends these photographs to rub it in. To make sure I suffer as much as possible.’ She had taken out another cigarette and was struggling with a disposable lighter. ‘He’s showing me how great his life is, now that I’ve got nothing.’

Anna stepped in and steadied Donna’s hand so she could light her cigarette.

‘Now that he’s taken away the only good thing I ever had.’

‘We’ll find her,’ Anna said.

‘I’m dead if you don’t, simple as that.’ Donna sucked hard at the cigarette, her cheeks sinking with each draw. ‘Dead in all the ways that matter, anyway. You lose a child, the best bit of you dies, that’s all there is to it.’

Anna stepped back. She pushed her hands deep into the pockets of her coat and looked at the pavement.

‘Any idea at all where he might be?’ Thorne asked. ‘I know you must have thought about it . . .’

‘Spain’s a bit obvious, but he did know a few people down there. Ex-business colleagues of one sort or another.’

‘Remember any names?’

‘You’d be better off asking some of your lot,’ she said. ‘The organised crime mob, or whatever they’re called now. We had so many of that bunch knocking on the door over the years that Alan was on first-name terms with most of them.’

If Langford was in Spain, it would certainly make sense to speak to the people Donna was talking about. These days that meant SOCA, so Thorne made a mental note to ask Brigstocke how he’d got on with them. Then he would chase up Dennis Bethell, see if his friendly neighbourhood pornographer had made any progress with the photographs.

‘We’ll be in touch,’ Thorne said.

Donna took care to give Anna a hug before turning and walking up the path. Thorne did not even warrant a goodbye. Standing at the car door, he could see Kate looking down from an upstairs window, though whether she was watching him or Donna, he could not be sure.

Thorne started the engine, cranked up the bluegrass CD. Then he turned and saw the look on Anna’s face.

‘What?’ He turned off the engine. ‘Anna?’

There were no tears, but it looked as though they might be on the cards. ‘It’s just all that stuff about her daughter,’ Anna said. ‘It upsets me.’ She shook her head, said, ‘Stupid,’ and glanced at him. ‘I’m sure you have to get . . . hardened or whatever to that kind of thing, what with some of the stuff you see. I mean, it’s just stories in the newspapers for the rest of us, you know? Dead kids . . .’

‘You don’t get hardened,’ Thorne said.

‘Sorry, I’ll be OK in a minute.’

‘Take your time.’

‘Have you got kids?’

‘No,’ Thorne said. He started the engine again, told her he would run her back to Victoria.

‘That’s miles out of your way.’ She rooted in her bag, pulled out a small pack of tissues. ‘Haven’t you got to get back to Hendon?’

‘It’s really not a problem.’

‘I’ll be fine,’ she said. ‘Just drop me at a tube.’

‘How did that go?’

Donna ignored the question, threw her coat across the banister and walked past her girlfriend into the kitchen. Kate followed, asked the same question.

‘Why would you care?’

‘Come on, Don . . .’

‘You’ve already made your opinion perfectly clear.’

Kate sat at the small table. ‘Look, I was just warning you about getting your hopes up.’

‘My hopes?’

‘I don’t want you to be miserable.’

‘You’re making me miserable, because you’re not supporting me.’

‘You’re wrong,’ Kate said.

‘I don’t need people being negative.’ Donna slapped her hand against a cupboard door. ‘I’ve had years of that. I need you to back me up.’

‘I’ve always backed you up. I’m just saying go steady, that’s all. You’re pinning everything on that copper and that soppy girl and if you’re not careful—’

‘What?’

‘You just might be in for a shock, that’s all.’

‘You think she’s dead, don’t you?’

‘I never said that.’

‘You think my Ellie’s dead? I will not listen to that crap.’

‘You’re not listening to anything . . .’

Donna flicked the kettle on, paced up and down the five feet of worn linoleum. ‘I know what this is about,’ she said.

‘It’s not about anything, OK? I just think you need to be realistic.’

‘You’re threatened by her,’ Donna said. ‘You’re threatened by Ellie.’

‘Don’t be stupid.’

Donna nodded, suddenly sure of herself. Spitting out the words. ‘You think that if I had my daughter around, I wouldn’t have time for you. You’re scared shitless about being number two.’

‘You’re pathetic.’

‘I should have worked it out before,’ Donna said. ‘Same as when we were inside. You were always a stupid, jealous bitch.’

‘How can I be jealous of someone who isn’t even here? Someone you don’t even know?’

‘I know you, though,’ Donna said. ‘I fucking know you!’

‘You don’t know anything.’ Kate stood up and walked to the door. ‘You don’t know anything, and I can’t help you.’

They stared at each other for a few seconds, until Kate turned and walked out. Donna leaned against the kitchen worktop, feeling the anger and the panic wheeze in her chest as the grumbling of the kettle grew louder behind her.