Overhead on the bridge, the traffic is much lighter between Cambridge and Boston’s Back Bay. There aren’t many cars or motorcycles, mostly trucks at this hour as the Charles River flows sluggishly like molten glass in the uneven glow of lamps along the shore. The helicopter is gone, at least for now, and our footsteps are quiet.

“What’s really going on?” I ask. “I know what I think but would rather hear your side of things.”

“Uh-oh. We’re already talking about sides.”

“Because you can’t be on mine and I won’t be on yours. Despite Marino’s claims to the contrary, I’m not married to the FBI.”

“I wanted to check on you for a lot of reasons, and it was important I tell you myself about Briggs. But that’s not the only reason I’m here.”

“Obviously not. You’ve been walking around and asking questions about a case that shouldn’t be any of your business. You don’t simply show up and insert yourself into a local investigation, and that tells me other things have gone on. Clearly they’ve gone on stunningly fast, in the blink of an eye.”

“Yes, they have because so much has happened at once,” and he tells me that before he got here he was on the phone with Gerry Everman, the commissioner of the Cambridge Police Department.

Benton doesn’t say who initiated this conversation, but I can guess. The FBI did, and when they take over an investigation this is what it’s like. It feels exactly the way it does right now as I walk with their senior profiler through the park toward densely shadowed trees beyond the clearing.

I listen to our shoes on the hard-packed path with its loose sandy surface that’s a poor medium for footwear or tire tracks. Distant traffic sounds like a gusting wind. I catch fragments of conversation in the impenetrable dark, and am vaguely aware of people I can’t quite make out talking in hushed voices.

I feel eyes on us as I catch the silhouettes in uniforms and field clothes of cargo pants and polo shirts. Cops, possibly the Feds, and I think about Harold implying it was getting a little crowded out here.

“ELECTRICAL? I GET THE impression that’s what you’re deciding.” Benton is almost too quiet to hear, and I walk very close to him. “It seems she was riding past a lamp and was electrocuted.”