“What happens on the ninth letter in the clue?” Flint asked. “There are only eight digits in the key—if it even is a key.”
“You just keep repeating the date over and over,” she said. “So the ninth letter would go back to having a zero above it.”
She finished writing and stood back. “Now for the decryption,” she said, the familiar rush of solving a puzzle quickening her words. “Going back to the beginning, the first letter was an S, right?” She waited for both men to nod. “Since the first number was a zero, you don’t shift the code at all. The first letter in the answer is S.”
She bent to write an S on the bottom of the page. “The next letter is Q, and the next number is five, so you shift the alphabet five letters.”
“Which direction do you go?” Wu asked.
“Good question,” she said, enjoying herself despite the gravity of the situation. “It could go either way, but since English reads from left to right, most people encrypt in that direction.”
“Which means you’d go the opposite way to decrypt,” Wu said.
“Exactly.” She gave Wu a smile. He was every bit as intelligent as she’d heard. “So the Q would become an L.” She jotted the letter down.
“That means the next letter, which is a G, would shift two letters and become an E,” Flint said, proving he was just as quick.
“Let’s see what we get when we use Doyle’s birth date as the key for the whole thing,” she said. “Based on the first three letters, I think that’s correct.”
A minute later, she straightened. All conversation halted for a moment as everyone took in the revealed message. Dani wrote it on two lines as it appeared in the original version.
SLEDGETAKESBRIBES
PROOFINPIC
“The first part is pretty damned clear,” Flint said. “Sledge takes bribes.”
“Now we know you were right about the date shift code,” Wu said to her. “But I’m not clear on the second line. It looks like it says, ‘proof in pic.’” He looked from the notepad to Dani. “Where is it?”
She recalled a photograph of a mountain range her team had taken from an enemy stronghold during her last deployment. After close analysis, they discovered the seemingly innocuous image concealed a map and a list of targets. She met Wu’s inquisitive gaze. “Steganography.”
“I know you’re not talking about a court recorder or a dinosaur.” Flint’s Brooklyn accent added an extra layer of sarcasm to the remark. “So how about you explain what that is?”
“It’s a way to conceal information inside text, sound, images, or objects,” she said, trying to explain the concept. “Someone downloaded this photograph from an open source, then digitized it. After that, they could embed all kinds of data into it.”
“It’s not a digital image now,” Wu said. “It’s a printed copy. How are we supposed to extract any data hidden inside?”
“As long as the image has sufficient quality, there are computer programs with algorithms designed to do that,” she said. “I’ve used them before.” She turned to Johnson, who had abandoned her keyboard to listen in on Dani’s explanation. “I need you to scan the photograph of Doyle and send it to cryptanalysis as a digital file. Tell them it’s a stego-image. They’ll know what to do.”
When Johnson crossed the room to retrieve the sheet of paper, Dani touched her forearm to stop her. “Don’t upload it to the main server,” she told the analyst. “It could contain malware.”
“Of course,” Johnson said, and Dani couldn’t tell whether the sharpness of the response indicated irritation that Dani had thought it necessary to warn her or that she had been about to load the document directly into the FBI’s internal server.
The JTTF had several stand-alone computer systems that allowed access to the internet and to an interconnected web between them, but not into the Bureau’s system. Digital evidence often came from a variety of sources, some of them definitely shady, and it made sense to open those files only in a walled-off virtual environment.
Wu interrupted Dani’s musings with a question. “We haven’t found anything in Nathan Costner’s background to indicate he has the capability or knowledge to produce this kind of coded message,” he said. “Who created this document?”
“His best friend said someone sent him the proof,” Dani said. “Costner was supposed to do his own research to corroborate the caller’s statements, then take what he found along with the envelope to a reporter.”
“How would a reporter decode the message?” Flint asked.
She chewed her lip in thought. “He must have figured Costner would reach out to a highly seasoned investigative reporter at a big news organization. Someone who would have access to plenty of resources.”
“The chief of staff couldn’t decode the message by himself,” Wu said. “And he wouldn’t go to the media without making damn sure there was evidence that the senator was corrupt. The scheme puts the entire burden on Nathan Costner to expose Sledge while the caller hides in the shadows and watches the scandal unfold. Brilliant.”
“Only Costner didn’t have the same distrust of the FBI,” Dani said. “He made sure his friend took the evidence directly to us in the event of his death.”
“You realize what this means?” Wu said. “The caller must have encrypted the evidence but described the allegations to Costner verbally. As the senator’s chief of staff, he was in the best position to corroborate the claims.”
Another piece clicked into place. “Sledge must have caught Costner going through his files,” she said. “Or maybe Costner confronted him.”
“If that’s true, the senator is not just corrupt,” Flint said. “He’s a murderer.”
“And a conspirator,” Dani added. “He hired Toro.”
Wu shook his head. “I’ve investigated my fair share of powerful people. They don’t get their hands dirty, and there is never a direct link to their crimes.”
“Okay, so we won’t find a check written out to Toro with ‘murder for hire’ in the memo line,” she said. “But maybe we can connect them with phone calls, money transfers, or CCTV footage of a meeting somewhere in the city.”
Wu countered the suggestions one at a time. “Burner phones, overseas banks, and intermediaries.”
Nailing a high-ranking official wasn’t going to be easy. Then again, she wasn’t used to easy.
“Then we break the chain at its weakest point,” she said. “We find Toro and squeeze him.”
“In the meantime, we prepare evidence to use as leverage,” Wu said. “A pro like Toro won’t talk unless we have him cold.”
They all digested this for a moment before Johnson interrupted the silence. “There’s something else you all should see.”
The main wall screen flashed a vivid blue, then connected with a local news feed.
“Senator Sledge is in town,” Johnson said. “And he’s holding a live news conference right now.”
CHAPTER 9
Dani swiveled her chair at the conference table to get a better view of the live news feed Johnson had transferred to the wall screen. The situation room fell silent as Senator Sledge strode out of the massive early-twentieth-century modernist-classical-style building where he maintained one of several offices spread throughout the state. He walked down a set of stone steps to a lectern bristling with microphones. Dressed in an impeccable blue suit paired with a burgundy silk tie, he raised his hands to bring order to the jostling crowd of reporters before him.
“This is a sad day for everyone who works with me,” he began in somber tones. “My chief of staff, Nathan Costner, was murdered today walking down the street. He had just bought coffee for the rest of the staff, something he did every Monday morning to brighten everyone’s week. That’s the kind of person he was. Always thinking of others. Generous to a fault. And now he’s . . . gone.” The last word came out as a hoarse croak. Sledge tugged out a handkerchief and dabbed at the corners of his eyes.
Dani had a saying: They’re not crying unless you see real tears and snot. The senator’s performance was impressive, but her bullshit detector was blaring.
Still clutching the handkerchief, Sledge composed himself and continued. “Nate was on his way to a meeting with me. We were going to discuss new legislation I’m proposing.” He leveled an intense gaze on his audience. “And I take responsibility for his death.”