He goes to fetch her order, using the queuing time as an opportunity to examine her more closely. She sits perfectly still and upright. Rabbani tries her best to make conversation, but Sophie Denham shuts her down each time with the barest of smiles. She seems out of place here, surrounded by partying students whose motivations for attending university differ widely from her own. But she’s unembarrassed about it. He struggles to work out how the chaotic Oscar might fit into this tidy, focused life.

When he returns she seems to have softened a little. “Thanks,” she says. Perhaps the banana did the trick. By contrast Rabbani looks ready to take the girl down and restrain her. He doesn’t know what was said but it’s clear Denham got the upper hand.

“I’m sorry,” she says, “I don’t have very long.”

“This shouldn’t take long.”

She eats the banana in small bite-sized chunks, breaking them off with fingernails neither long nor short, coated in clear nail polish. “To be honest, I don’t really know what I can tell you.”

“We’re speaking to as many people as we can who are involved with the case.” He watches her chew; everything about her is so measured and precise. “You were at school with Oscar Cartwright, is that right?”

“Childhood sweethearts,” she says. She laughs but it sounds a little forced. “All very romantic. There was a group of us used to hang out together, usually up at the vicarage; there was always something to do there. Oscar used to have this enormous treehouse, and there was always the chance Edna or Lil had been baking. We got to do pretty much what we wanted, no parents to tell us off.” She laughs again. “It was a teenager’s dream house.” Then the laugh fades away. “I only met Gerald a couple of times. He was hardly ever there.” She’s a little too quick to distance herself from Cartwright.

She takes a sip of tea, and he gets the impression there’s something else. Something she wants to tell him. Then a thought occurs to her and her face changes. “Is Oscar a suspect?” she asks, appraising him with the professional cynicism of a hardened defense attorney.

“Just routine,” he says. “How is he taking all this?”

She answers slowly, obviously working out the best way to phrase her response. “He’s doing well. Considering.” She falters, perhaps worried she’s made Oscar sound too cool about the situation. “I mean, he’s not great, obviously.” Now she blushes; she’ll have to learn to control that when she goes to court. “I haven’t seen that much of him lately, to be honest. Apart from last night.”

Last night. The words clatter around his head. She was with him as recently as last night.

“Is that unusual?” Rabbani asks.