“You’ve got to be kidding.”

The math equation covered the whole area from his waistband to his shoulder blades. I’d never seen anything like it. Not in this context anyway. Sampson motioned the scene photographer over to get a shot.

“This is new,” John said. “The last numbers were just on the face. Makes me wonder if our guy’s been practicing. Maybe other bodies we haven’t found.”

“Well, he definitely wanted you to see this one,” Porter told us. “That’s the other thing. There’s not near enough blood here for the amount of blunt force trauma. Someone pounded this kid, then brought him here, and then did the fancy knife work.”

“Doo-doo, doo-doo.” The photographer let out a snatch of The Twilight Zone theme before Sampson stared him down. “Sorry, man, but… damn, I’m glad I don’t have your jobs today.”

Him and everyone else.

“So the question is, why bring him here?” Sampson said. “What’s he trying to say to us? To whoever?”

Porter shrugged. “Anyone speak math?”

“I know a prof at Howard,” I said. “Sara Wilson. You remember her?” John nodded, still staring down at those numbers. “I’ll give her a call if you want me to. Maybe we can head up there this afternoon.”

“I’d appreciate it, that’d be good.”

So much for my quick consult. I had no time for this, but God help me, now that I’d seen the damage this perp was capable of, I wanted a piece of him.

Chapter 58

I’D KNOWN SARA WILSON for more than twenty years. She and my first wife, Maria, were freshman roommates at Georgetown and remained good friends until Maria’s death. Now it was just Christmas cards and the occasional chance meeting between us, but Sara hugged me hello when she saw me and still remembered Sampson by name — first and last.

Her tiny cell of an office was in the unimaginatively named Academic Support Building B on the Howard campus. It was crammed with bookshelves to the ceiling, a big sloppy desk just like mine, and a huge whiteboard covered in mathspeak, in different colors of dry-erase marker.

Sampson took the windowsill, and I sat down in the lone guest chair.

“I know you’ve got exams coming up,” I said. “Thanks for seeing us.”

“I’m happy to help, Alex. If I can help?” She tipped a pair of rimless specs off her forehead and looked down at the page I’d just handed her. It had transcripts of the numbers and equations that were found on the victims. We also had crime-scene photos with us, but there was no reason to share the gory details if we didn’t have to.

As soon as she looked at the page, Sara pointed at the more complicated of the figures.