Page 9 of Go Under

That was also a hallmark of the Commandment Killing ciphers. The opening sentence was always the simplest. It was the part always meant for the world. While some killings included larger and more general messages, others continued with more personal messages, directed specifically at Kate. Oftentimes, those specific messages were hidden behind what seemed like ordinary rhetoric, but there was always a clue, always something they added to let Kate know that Cox was thinking about her.

The rest of this cipher was more difficult to figure out. Basic substitution yielded gibberish, and double substitution yielded the same.

Kate wasn’t cowed, though. She’d joined the FBI after dropping out of graduate school in linguistics with an emphasis in encryption and cryptography. She had far more experience decrypting codes than this killer had making one.

And with patience and care, the cipher began to reveal its secrets. A word here, a line there, and little by little, Kate pieced together the message.

And confirmed that this one was meant for her. The second line of the cipher, the one directly underneath the verse, read, daughter of the false healer, know this.

Kate’s lips thinned. The prior May, Quinn Marsh had corrected people who broke the fifth commandment, “Honour thy Father and Mother.” When Kate finally tracked him down and confronted him, he told her of the death of his mother, a woman her father had chosen not to save in favor of another candidate for an experimental stem cell treatment. It was clear that he was the false healer, and Kate was his daughter.

This was the first time she’d been addressed so directly.

No, the second. In the last commandment killing case, Cox had eschewed a traditional cipher in favor of placing stolen objects in the homes of his chosen victims so that they pointed toward a specific location, St. Anselm’s Cathedral in Baltimore, formerly the Church of St. Simon and St. Jude.

That was as explicit as it got. In fact, the “cipher” seemed to reference the eighth commandment, “Thou Shalt Not Steal,” almost as an afterthought. The primary message was, look here, Kate.

This cipher so far appeared to emphasize both the commandment and the personal connection to Kate. But how had her father borne false witness? Surely, she would have come up with something during her exhaustive search of her father’s past. Surely Poppy, whose research skills bordered on superhuman, would have found something.

She kept working. She finished her first cup of coffee and poured another. She finished her cheesesteak and made it halfway through a bag of peanuts before folding the rest to save for later. Rather than starving herself as she had at home, her new focus apparently left her ravenous.

As the cipher slowly took shape, Kate began to understand the point of the message.

The more she understood, however, the more questions she had.

Marcus returned after dark. She looked up and noticed the darkness outside. Way after dark.

She checked her phone. Really way after dark.

“Did you find something?” she asked.

He sighed. “No. I talked to everyone on that street, and I grilled the officers who responded to the assault call, and no one saw anything or anyone out of the ordinary.”

Kate frowned. “No one saw a single person who didn’t belong in a neighborhood known for crime.”

Marcus poured himself a cup of coffee from the pot at the corner of the hotel room’s counter and took a big gulp, not seeming to notice either the temperature or the flavor. “That’s the thing about neighborhoods like that. I wasn’t being cute when I made that crack about ordinary urban background noise. When you live in a safe neighborhood, people notice when people don’t belong. When you live in a bad neighborhood, gunshots, fighting, shouting, and car alarms really are the background noise.”

“And no one thinks, ‘Hey, maybe if we took action and reported this, it would stop?’”

He chuckled. “Most people think, ‘If I mind my own business, I probably won’t get shot.’”

He downed the rest of his coffee in two enormous gulps, then poured himself another cup. He took a more moderate sip from that cup, then used it to gesture at Kate’s notes. “Did you have better luck?”

“Yeah,” Kate said, pushing a chair out so he could join her.

“I’ll stand.” She frowned, and he explained, “I’m pissed off. If I sit down, I’ll get anxious and get more pissed off. If I stand and listen to good news, I’ll calm down.” She kept staring, and he said, “Hey, don’t judge. I do what I have to do.”

She smiled. “No, it’s fine. I think it’s cute.”

The words slipped out before Kate considered their connotation. Marcus reddened a little and looked away. Heat climbed the back of her neck, and she cleared her throat and gestured toward her notes.

“I translated the cipher. It’s relatively short, especially compared to the monologues we got for the sixth and seventh commandments. It opens with the commandment, Thou Shalt Not Bear False Witness, then continues with a direct call to me. ‘Daughter of the false healer, know this. God’s law must be obeyed in word and deed, in body and mind, in soul and spirit. God knows all those who seek to circumvent His laws by skirting the literal meaning of the words and violating the hidden meaning of the Spirit.’”

“Dramatic,” Marcus said. He looked at Kate closely. “How are you?”

“I’m fine,” she said. “Actually, I’m really fine. I feel better than I have in weeks.”

He brightened. “Yeah?”