“We’ll inform your school if we need to keep you beyond the exam’s starting time.”

“But . . . that’s hours yet. You can’t . . .” He turned toward Ms. Lucas, who simply shook her head once.

“The exams can wait,” said Banks. “There’ll always be another opportunity. It takes as long as it takes, Jason. If you cooperate, we’ll be done in no time.” But you won’t be heading out to sit any exams, he thought.

Then Annie started up the recording machines and cautioned Jason. When Ms. Lucas had explained the caution to him, and he had said that he understood, they began.

“You know why we’re here, Jason,” said Banks. “Wouldn’t it be easier and quicker if you just told us what happened that Sunday night in the park?”

“What Sunday night? I don’t know what you’re talking about.”

“A week ago last Sunday, when you and Chris Myers were down in the little park at the bottom of Elmet Hill smoking marijuana.”

“We weren’t there. And you can’t prove anything.”

“Oh, yes, we can. We turned up quite a lot of evidence there yesterday, and the scientists have been working overtime on it.” He glanced at his watch. “We’re expecting the results any moment. We told them to bring what they found straight here to us.”

“I don’t believe you. Even if you did find stuff, you can’t know when it was put there, or who by.”

“If we find Samir’s blood, we’ll know that it wasn’t put there after that Sunday night, because that’s when he was murdered.”

“A bit melodramatic, Superintendent,” Ms. Lucas interjected.

“That doesn’t mean anything,” said Jason.

“What about if we find your DNA in the saliva on those roaches, or the chewing gum?”

“I don’t chew gum. What roaches?”

“Didn’t you know? We found two roaches in the woods there, close to where we found the blood. We think you were there smoking up when Samir turned up and you killed him. You forgot to take them with you when you left the scene. Sloppy, Jason.”

Jason said nothing. Banks thought he could hear the wheels turning.

“We know Chris was involved with drugs because he was caught at a drug party last year,” he went on. “You’re his best mate. It’s no great stretch to say you were involved, too, even if you weren’t at that particular party.”

Ms. Lucas whispered in Jason’s ear, and he said, “No comment.”

“How long have you been carrying a knife, Jason?”

“I don’t carry a knife.”

“But you were carrying one on the night we’re talking about, weren’t you? Why? Were you nervous about being in the park, about being out so near Hollyfield after your sister had been attacked? She said she was scared to walk through there by herself.”

“That’s stupid.”