“I started taking these the first day we saw the cars.” I watch him scroll slowly through the pictures. “This is the day they had the fight. We could hear their voices, but not what they were saying. Here’s Ms. Sullivan walking across the field by herself. You can tell she’s mad by the way she walks. And look, the man drives away so fast he skids on the gravel.”

“We think he went somewhere and then came back and found her in the woods,” Skylar says. “That’s when he killed her.”

Mr. Boyce scrolls through the photos and videos, then goes back to the beginning and scrolls again, pausing every now and then to study one. He’s upset, I can tell by his face and the way he stares at the pictures. Maybe it’s a mistake to show them to him when he’s so sad about Ms. Sullivan.

Finally Mr. Boyce puts the phone down and looks at Skylar and me. “I don’t understand why you took these pictures.” He makes it sound like we did something wrong. “What were you thinking?” he asks. “Why were you so interested in these people?”

Skylar discovers that her stool rotates, and she turns this way and that while she tries to explain. It’s the kind of thing she does when she’s nervous.

“We thought they might be criminals,” she tells him, “or spies like on that TV show about these supposedly ordinary Americans who are really Russian spies. It was a mystery. We wanted to solve it.”

Mr. Boyce sips his coffee slowly, his forehead wrinkled, as if he’s thinking. Finally he puts the empty cup down.

“What kind of advice do you want from me?” He sounds disappointed in us. Maybe we’re not so super-duper after all.

Skylar stops spinning and leans toward him. “Should we tell the police what we saw? Should we show them the stuff on the phone?”

Mr. Boyce gets up to brew another coffee. While he’s waiting for the machine to beep, he walks to the sliding door that overlooks the backyard. The glass is smeared with Andy’s fingerprints. The deck needs staining or painting or something, and the uncut lawn is weedier than the front yard. Big plastic toys are scattered around, some of them broken. A rusty barbecue tilts to one side. The ashes from the last time it was used are still in the grate.

For a few minutes he stands with his back to us, looking at the yard. He must miss Andy. Maybe that’s why weeds have taken over and the house is so dirty.

“What should we do?” Skylar asks in a louder voice. Maybe he didn’t hear her the first time.