Savich nodded, introduced both himself and Sherlock to Mr. and Mrs. Cronin, and out of habit, they showed them their shields. He said, “Please accept our condolences, though they aren’t enough, we know that, nothing could be. We are very sorry to intrude on you at this time, but we have to move quickly and we lost a day because of the blizzard.”

“We have heard of both of you,” Cronin said. “Avilla and I saw you Saturday morning, Agent Savich, speaking in front of the Lincoln Memorial. The news stations have been showing that clip all weekend. You didn’t know then that the victim was my grandson. We watched you like every other benighted human being, shocked and horrified, of course, at the finding of a frozen dead body at Lincoln’s feet. It doesn’t say much for the human race, does it, our rapt attention at our safe distance, to a violent death displayed for the world to see? Neither Avilla nor I thought you wanted to be standing there speaking to the media. You looked . . . angry, Agent Savich.”

“No, sir, I didn’t want to speak about it,” Savich said, “and yes, I was very angry.”

Avilla Cronin said from behind her husband, “Tell me now, Agents, do you honestly believe you will find the monster who murdered our grandson?”

“Yes, Mrs. Cronin, we do,” Sherlock said.

Palmer Cronin gave Sherlock a brief dismissive look and continued as if she hadn’t spoken. “Despite that revolting photo and where that poor boy was left, is the FBI considering the possibility that Tommy was murdered for personal reasons?”

Savich said, “It’s possible, sir. That’s one of the reasons we’re here, to find out more about him.”

Cronin studied Savich’s face for a moment. “But of course you know it’s a waste of time. Sit down, both of you.” He waved at two Art Deco chairs sitting opposite the rounded sofa. He shuffled back and sat down carefully next to his wife. Savich watched him take his wife’s thin hand in his, but he didn’t squeeze it. Their two limp hands simply rested against each other.

Cronin asked, “Do you know yet who posted that horrific photo of Tommy? Has anyone claimed responsibility?”

“Not yet, sir; we’re working on it.”

“Avilla and I have talked of nothing else, of course, and it seems obvious that a quiet, studious boy like Tommy would not have had an enemy who would go to such lengths to kill him and add the final humiliation of placing him at Lincoln’s feet. I do not wish to accept it, but Avilla tells me I must. He was killed because I am his grandfather, as revenge against me.

“What kind of insane person would hold Tommy accountable for my actions, any mistakes I may have made, even if he held me responsible for his financial misfortunes?”

“We will return to that, sir,” Savich said. “Bear with us.”

Avilla Cronin sat forward and said, her voice filled with the authority of someone who expects to be listened to, “No, answer him. My husband is correct. Tommy was too young to have such crazed enemies. The killer has made it obvious, has he not? A malcontent or a radical or an anarchist murdered Tommy, spurred on by all the media frenzy about those people in Zuccotti Park, or perhaps because he lost everything in the banking crisis. He wanted to make someone pay, and he selected Palmer, the most important and well-known face of banking in the world. He wanted to show the world he was getting revenge. Will he try to murder us next?”

Avilla was seventy-six years old, a year younger than her husband, the daughter of Boston shipping wealth and for nearly fifty years the wife of the powerful Palmer Cronin. In her early years she’d been outspoken, involved in the civil rights protests, and spent a few nights in jail. Later, she’d been managing director of MIS—Make It Stop—a charity organization that awarded antipoverty grants for economic development in the third world.

“We don’t know what he will try to do,” Savich said. “Until we make an arrest, we will do our best to protect you.”

She nodded. “Yes, Director Mueller said we would have an FBI agent to guard us. For that, at least, we are grateful.” Her strong face collapsed, but she didn’t cry, she sat there frozen, her hand now clutching her husband’s.

“What I find difficult to understand,” Mr. Cronin said, “is why anyone would wait so many years after I resigned my position as the Federal Reserve chairman?”

Savich nodded in agreement. “Mr. Cronin, your staff has forwarded to us the file of threatening letters you’ve received in the past two years. If need be, we will look back all the way to 2008. Have you personally received any threats, sir?”