It was my mug.

“I poured the tea out in the bathroom sink,” he whispered, holding it against his chest with both hands.

“But I kept the cup.

I thought the police might need it.” I put my arm around my son and did not trust myself to speak.

Somewhere between the office and the gate, my eleven-year-old had thought further ahead than I had.

He had understood, without anyone teaching him, that a story is one thing and evidence is another, and that grown-ups believe the second in rooms where they doubt the first.