John Stewart had told Nkata to take it. Nkata had asked Barbara to accompany him. By the time they got there, it was ten o’clock at night. They could have waited till morning-they’d been working fourteen hours at that point and they were both knackered-but neither one of them was willing to wait. There was a chance that Stewart would hand this job over to someone else, and they didn’t want that.

Sergeant Starr turned out to be a black man, slightly shorter than Nkata but bulkier. He had the look of a pleasant-faced pugilist.

He said, “We’ve already had this yob in for street brawling and arson. Those times, he’s pointed the finger elsewhere. You know the sort. It wasn’t me, you fucking pigs.” He glanced at Barbara as if to ask pardon for his language. She waved a weary hand at him. He went on. “But the family’s got a whole history of trouble. Dad got shot and killed in a drug dispute in the street. Mum toasted her brain with something, and she’s been out of the picture for a while. Sister tried to pull off a mugging and ended up in front of the magistrate. The aunt they live with hasn’t been willing to hear shit about the kids being on the fast track to trouble, though. She’s got a shop down the road that she works in full-time and a younger boyfriend keeping her busy in the bedroom, so she can’t afford to see what’s going on under her nose, if you know what I mean. It was always just a matter of time. We tried to tell her first time we had the kid in here, but she wasn’t having it. Same old story.”

“He talked before, you said?” Barbara asked. “What about now?”

“We’re getting sod all out of him.”

“Nothing?” Nkata said.

“Not a word. He’d probably not’ve told us his name if we hadn’t already known it.”

“What is it?”

“Joel Campbell.”

“How old?”

“Twelve.”

“Scared?”

“Oh yeah. I’d say he knows he’s going away for this. But he also knows about Venables and Thompson. Who bloody doesn’t? So six years playing with bricks, finger-painting, and talking to shrinks and he’s finished with the criminal-justice system.”

There was some truth in this. It was the moral and ethical dilemma of the times: what to do with juvenile murderers. Twelve-year-old murderers. And younger.

“We’d like to talk to him.”

“For what good it’ll do. We’re waiting for the social worker to show.”

“Has the aunt been here?”

“Come and gone. She wants him out of here directly or she’ll know the reason why. He’s going nowhere. Between her position and ours, there wasn’t a hell of a lot to discuss.”

“Solicitor?”

“I expect the aunt’s working on that angle now.”

He gestured for them to follow him. On their way to the interview room, they were met by a worn-out looking woman in a sweatshirt, jeans, and trainers, who turned out to be the social worker. She was called Fabia Bender, and she told Sergeant Starr that the boy was asking for something to eat.

“Did he ask or did you offer?” Starr inquired. Which meant, of course, had he opened his mouth to say something at last?

“He asked,” she replied. “More or less. He said, ‘Hungry.’ I’d like to fetch him a sandwich.”

“I’ll organise it,” he said. “These two want a word. You see to that.”

Arrangements made, Starr left Nkata and Barbara with Fabia Bender, who didn’t have much more to add to what the detective had already told them. The boy’s mother, she said, was in a mental hospital in Buckinghamshire, where she’d been a repeat patient for years. During this most recent round of institutionalisation, her children had been living with their grandmother. When the old lady decamped for Jamaica with a boyfriend who was being deported, the children got passed off to the aunt. Really, it was no surprise that kids found their way into trouble when their circumstances were so unsettled.

“He’s just in here,” she said and shouldered open a door.

She went in first, saying, “Thank you, Sherry,” to a uniformed constable who apparently had been sitting with the boy. The constable left, and Barbara entered the room behind Fabia Bender. Nkata followed, and they were face-to-face with the accused killer of Helen Lynley.

Barbara looked at Nkata. He nodded. This was the boy he’d seen on the CCTV film taken in Cadogan Lane and in the Sloane Square underground station: the same head of crinkly hair, the same face blotched with freckles the size of tea cakes. He was about as menacing as a fawn caught in the headlamps of a car. He was small, and his fingernails had been bitten to the quick.

He was sitting at the regulation table, and they joined him there, Nkata and Barbara on one side and the boy and the social worker on the other. Fabia Bender told him that Sergeant Starr was fetching him a sandwich. Someone else had brought him a Coke although it remained untouched.

“Joel,” Nkata said to the boy. “You killed a cop’s wife. You know that? We found a gun nearby. Fingerprints on that’ll turn out to be yours. Ballistics’ll show that gun did the killing. CCTV film places you on the scene. You and ’nother bloke. What d’you got to say, then, blood?”

The boy slid his gaze over to Nkata for a moment. It seemed to linger on the razor scar that ran the length of the black man’s cheek. Unsmiling, Nkata was no teddy bear. But the boy drew himself in-one could almost see him call upon courage from another dimension-and he said nothing.

“We want a name, man,” Nkata told him.

“We know you weren’t alone,” Barbara said.

“Th’ other bloke was an adult, wasn’t he? We want a name out of you. It’s the only way to go forward.”

Joel said nothing. He reached for the Coke and closed his hands round it, although he did not attempt to pop it open.

“Man, where you think you’re going for this one?” Nkata asked the boy. “You think we send blokes like you to Blackpool for a holiday? Going away is what happens to the likes of you. How you play it now determines how long.”

This wasn’t necessarily true, but there was a chance that the boy wouldn’t know it. They needed a name, and they would have it from him.

The door opened then and Sergeant Starr returned. He held the triangle of a plastic-wrapped sandwich in his hand. He unwrapped it and passed it over to the boy. The child picked it up but did not take a bite. He looked hesitant, and Barbara could tell he was struggling with a decision. She had the sensation that the alternatives he was considering were ones that none of them would ever be able to understand. When he finally looked up, it was to speak to Fabia Bender.

“I ain’t grassing,” he said and took a bite of his sandwich.

That was the end of it: the social code of the streets. And not only of the streets, but the code that pervaded their society as well. Children learned it at the knees of parents because it was a lesson essential to their survival no matter where they went. One did not sneak on a friend. But that alone told them volumes in the interview room. Whoever had been with the boy in Belgravia, there was a strong possibility that he was considered-at least by Joel-a friend.

They left the room. Fabia Bender accompanied them. DS Starr remained with the boy.

“I expect he’ll tell us eventually,” Fabia Bender assured them. “It’s early days yet, and he’s never been inside a youth facility before. When he gets there, he’ll have another think about what’s happened. He isn’t stupid.”

Barbara considered this as they paused in the corridor. “He’s been in here for arson and a mugging, though, hasn’t he? What happened about that? A wrist slapping by the magistrate? Did things even go that far?”

The social worker shook her head. “Charges were never brought. I expect they didn’t have the evidence they wanted. He was questioned, but then he was released both times.”

So he was, Barbara thought, the perfect candidate for some sort of social intervention, of the kind provided in Elephant and Castle. She said, “What happened to him then?”