Ms. Grady looked like she was trying to decide something. She sighed. “I’m sorry, Rosa, but I need to take this to the office. You know the rules. You can collect it there after school.” Now the whole class was staring at her, World War II forgotten.

Fine, Rosie thought, her face burning. So what if Ms. Grady had seen Maddie’s texts? Maybe the principal would haul Brendan and his dumb friends into the office and get the pictures, and she wouldn’t have to do it herself.

She slouched down in her chair and forced her attention back to the TV, wincing along with everyone else as the hero narrowly avoided stepping on a land mine.

Detective Murray received a call from the high school office and turned his car around, checking his mirror and pulling a U-turn on River Road that made gravel spin out from under his tires. It wasn’t necessarily an emergency, but getting to drive like that was a perk of the job.

The secretary, growing accustomed to his visits, showed him directly into Dr. Johnson’s office, where the principal had a bright pink Motorola flip phone sitting on his desk.

“I thought you’d want to hear about this,” Dr. Johnson said. “Ms. Grady confiscated the phone during class, after she saw that the student was communicating about pictures of the party.”

“Who is the student?” Murray asked, pulling out his notebook.

“Rosa Mendoza,” Ms. Grady said. “She’s a good student. I was surprised she was texting, to be honest, but they all get antsy toward the end of the year.”

The name didn’t ring a bell for Murray. He thought quickly. He would need to show probable cause to legally search the phone. “Did you actually see these pictures?” he asked Ms. Grady.

“No,” Ms. Grady admitted. “But they were definitely being discussed. I brought the phone in to Dr. Johnson as soon as my class wrapped up.”

Murray only hesitated for a moment. He thought it was unlikely the girl would just give him permission to search her phone. He knew he was crossing the line, but he decided to take a quick peek. He opened the phone and the screen lit up. Neither Dr. Johnson nor Ms. Grady objected. In fact, they were looking at him expectantly.

The text conversation that Ms. Grady had seen was still open, and Murray’s pulse quickened when he saw the name Maddie. Madison Martin was the girl who’d reported her assault, and although any pictures from the party would be helpful, what Murray really needed were the pictures that she’d told them about. With photographic evidence, they’d have a much stronger case. Since she hadn’t come forward right away they had no physical evidence, and the witnesses were a bunch of drunken teenagers, many of whom were facing charges themselves. It wasn’t a lot to go on.