“Who do you think you were actually talking to when you saw the 202 area code for D.C. and took the call?” I ask. “Did you assume it really was an NCB investigator?”

“I wasn’t sure what was going on at first. The person sounded male and reasonably credible until he launched in about the developing Maryland investigation. That was the language, and I had no idea what investigation he was talking about. So I listened, and I asked why he was calling me specifically and how he got my cell phone number. He said I was listed as the contact person on the case.”

“What case specifically?” I look down at my shoes, and one of the heels is coming loose.

“In hindsight, obviously Briggs, who I wouldn’t know about until a little bit later. But at the time this so-called NCB investigator was vague. When I pushed him on details he was in a hurry. He gave me a phone number that turns out to be the desk of the Hay-Adams Hotel.”

“And since that’s exactly what happened to Marino,” I reply, “it can’t be a coincidence.”

“I agree. Two bogus phone calls within minutes of each other, both supposedly from NCB about two different cases that have barely happened yet, mysterious sudden electrical-type deaths occurring almost at the same time hundreds of miles apart,” Benton says, and I remember him in the drawing room of the Faculty Club, on the phone near the grand piano.

“When this so-called investigator was talking to you, did you notice if he coughed?”

“It’s interesting you would say that. Yes, he sounded like he might have asthma.”

It’s possible Carrie is utilizing voice-altering software, and I wonder if she’s sick or maybe her accomplice is. Benton may have been talking to one of them and had no idea. It’s even more bizarre to think Marino might have been. I touch the left arrow at the bottom of the phone’s display to go back a screen to see who e-mailed the photograph.

Tailend Charlie sent it to Benton’s FBI e-mail address some four hours ago, last night at eight P.M. This was an hour and fifteen minutes after Ruthie discovered her husband in the pool, and maybe forty-five minutes after the twins discovered Elisa Vandersteel’s body here in the park and helped themselves to her phone, calling 911.

“We’re supposed to know Briggs was a hit,” Benton says. “That’s why I got the photograph. It’s a way of claiming responsibility. Calling Marino was a way of doing the same thing about the case here in Cambridge. It’s what terrorists do, and never forget that’s what Carrie Grethen is. She and whoever she’s in league with are terrorists who won’t stop until they’re eliminated.”

“I’m glad she’s telling us what she thinks we need to know.” I feel a prick of anger.