“They do remember Latham often chatting up the ladies, but not being obnoxious about it. He was okay just being a guy, watching the Celts and the Patriots on the screen with the locals. He owned his car. To me, he’s suspicious because he was so unsuspicious. For a guy who was murdered so brutally, he was trying to keep his outward appearance squeaky clean.”

“Did his colleagues have anything to add?”

“Nope. Just a typical visiting lecturer. He shared an office with four other lecturers but they rarely see one another because their schedules are different. One of the gals I spoke to said she doesn’t even work there because the space is so small. She works at home and only uses the shared space for posted office hours with her students. People don’t remember him hanging around the campus too much. But everyone I spoke to about Latham did say he was very knowledgeable about his field, which was . . .”

Mulrooney flipped through his notes.

“Here we go. The official title is History of Art and Propaganda in the Soviet Union. It was an upper-division class for majors in art, history, and art history; and he had forty students, which is a very big number. We’ve interviewed almost all the students and have come up empty. If the codebook doesn’t tell us something, we’re shooting in the dark. And that’s really making all of us nervous after what happened to you guys down there.”

Oliver said, “Deck thinks we’re dealing with foreign criminals.”

“Yeah, even stupid people usually don’t take out detectives. And when they do try, it’s usually to prevent testimony. Somebody clearly doesn’t know the rules.” Mulrooney hesitated. “Which foreign country? Are you thinking Russia because of Latham’s specialty?”

“Yes, exactly,” Decker said. “Latham’s takeout was very surgical. Maybe it’s not even the Russian mob. Maybe it’s Russian spooks.”

“That would be very bad,” Oliver said.

“It certainly would mean we’re over our heads. But I don’t have anything to go on other than a queasy feeling.”

“This is making me very, very nervous,” Mulrooney said.

“Yeah, you and me both,” Decker said. “But I’m not about to back off before I find out why someone wanted me dead. Maybe the answers will be in the codebook.”

No one spoke for a minute. Then Mulrooney said, “Maybe we should take the book to Quantico. I know we don’t have anything to tell them, but we can’t figure out the code on our own and I’m nervous about involving a Harvard math professor in something so potentially dangerous.”