"There has to be something else we can do," said Colby, as he leaned against a table in the FBI conference room, hands in his pockets.
"The drug-runners' accomplices got away before we could put out the call and block off roads. We're searching the area, but we don't have a lot to go on," said Megan.
Just then, Charlie burst through the conference room's glass doors, his curly hair bouncing wildly as he rushed into the room. His eyes were wide with concern, and he began tapping his hand against his leg with a nervous fervor.
"I just got the message. What happened? Who did this?"
Megan met him halfway and gently put her hand on his shoulder.
"We don't know who grabbed Don exactly, Charlie, but they're probably connected to the drug ring we were investigating. All we know is that sometime after 8 a.m. but before 8:15, someone managed to get Don out of the house we were raiding and through our perimeter before we even knew what had happened."
She pressed her lips together in a grimace, and patted Charlie's shoulder.
"But why?" asked Charlie
"I can think of a lot of reasons, but the two that stick out the most? Either they want to have some leverage for a trade or…" Colby trailed off.
"Or what?" asked Charlie, his voice panicked.
Colby's eyes glazed over for a moment as he remembered some of the things he'd seen happed to prisoners of the enemy when he was in Afghanistan. Drug runners with a vendetta against the FBI could and would beat and seriously injure Don—or worse. Charlie didn't need to be thinking about that right now.
He took a deep breath and met Charlie's gaze. "Charlie, let's focus on the first possibility."
Charlie nodded absently, and it was like someone had flipped a switch in his brain. "Data. What data do we have to work with? More data is always better. Knowing the full set of possible motives should help me refine a possible path."
He paused and noticed the grave expressions on Colby and Megan's faces.
"What aren't you telling me?" asked Charlie, as he paced in front of the table.
"We don't know anything for sure, Charlie, but it's possible they've got something against the FBI, and they want to take it out on someone," Colby said with a frown.
Sitting down heavily in a chair, Charlie took a deep breath.
"But," said Colby, "we haven't received any sort of demands or publicity-seeking photos or video from whoever took Don. There's no way they don't know they have an FBI agent. I wish I knew what they're waiting for."
Charlie furrowed his brow and sat quietly for a while, thinking. Megan's phone beeped with a text alert, and she pulled it out of her pocket to look at it. Charlie found himself staring at the phone in her hand.
"We know where Don's kidnapper was at a specific time, right?" said Charlie.
"Well, yeah. But Charlie, he left Don's phone at the scene. We can't track him that way," said Colby.
Smiling slightly, Charlie said, "We don't need Don's phone. We'll use the kidnapper's."
"I know you want to help, Charlie, but he didn't exactly leave us his phone number," said Colby.
Charlie jumped up and walked to a whiteboard. Uncapping a marker, he drew three overlapping circles.
"Doesn't matter. Remember the blackouts? We tracked their target by seeing what didn't overlap. We're going to do the opposite here. Imagine three people shining flashlight on the ground from different directions. The spot where they all intersect will have the most light. We'll need data from this morning from the three nearest cell towers surrounding the house where you made the bust."
Megan furrowed her brow in confusion. "I'm still not following you, Charlie."
"By using the overlapping data from the three towers, we can narrow down a geographic area around the house and use it to reduce our suspect pool," Charlie explained excitedly, as he colored in the area where all three of his circles overlapped. "We're going to pinpoint all the cell signals that were in a one-block radius of the house from this morning."
"That's going to be a lot of cell signals," Megan said with a frown.
"From there, we whittle it down. Eliminate those that belong to the FBI, and those that were still in the area at 8:30 and after. Then, we can shrink it further by seeing where the remaining signals are now," Charlie said, scribbling an equation on the whiteboard. "But first we need the data."
For the first time all afternoon, Megan smiled. "I'll get a warrant."
Hours later, Charlie was still furiously scribbling on a whiteboard while David and Colby helped with loading the databases and typing in other information.
"So, how are we doing here?" Megan asked, walking back into the room.
Charlie paused and ran a hand through his curls.
"I'm writing an algorithm to isolate the overlap-area cell signals in this data that got hits from all three of these towers in our given timeframe— from the time you entered the house to 15 minutes after you discovered Don was missing."
"OK, then what?"
"Once we get those results and remove other numbers we know aren't the person, then we ping the remaining phones and get their current locations. I can figure out the probability of each suspect being the right person based on their current location."
"A kidnapper could really be anywhere, so what factors are you figuring into your probabilities?" said David.
"Well, for instance, it's unlikely that our bad guy is taking the time for a long dinner at a nice restaurant or spending the evening at a movie theater. He's most likely going to stick with Don-" Charlie's voice caught in his throat as he mentioned his brother, but he continued. "To keep an eye on him."
"Right, I see where you're going, Charlie," David said, nodding. "So you'd give higher numbers to isolated locations or neighborhoods where no one would ask too many questions about something strange?"
"Exactly," Charlie said, pointing at David. "So when we run the initial algorithm, we get 200 cell signals in the overlapping area at 8 a.m. If I eliminate all FBI and other emergency personnel and all the signals that remained in the area after we know this guy left, that already brings us down to 50. Now we just have to use the current locations, and we'll have our most likely search areas."
"This is great, Charlie," Colby said. "As soon as you have it narrowed down, we'll get teams out to the hot zones."
Colby started to walk out the door, then turned back to Charlie. "We'll get him back, Charlie. I promise."
"I can't believe Charlie managed to narrow it down to two places. After three years, I shouldn't really be surprised, but sometimes I feel like Charlie's math is almost a magic trick," said David.
Colby looked out the window. "We're almost there. Megan's team is already in position at the second location."
David guided the sedan into a complex of warehouses. Stacks of broken pallets littered the alleyways, and an empty soda can clanked across the parking lot, propelled by a slight breeze. He pulled in next to a large steel-doored building. The bulky black SWAT truck was already there.
"OK, staging area is here," David said. "Is SWAT in position yet?"
Colby pressed the button on his radio.
"This is FBI team one to SWAT team leader. What's your position?"
A blast of static poured out of the radio.
"This is SWAT team leader. We are in position, ready to go on your signal."
David and Colby stepped out of the car and pulled their gear from the back. Suited up in Kevlar and carrying their weapons, they walked over to the edge of the first warehouse.
David pointed to another warehouse 25 feet away. "We've got the front, SWAT's got the back and side."
He turned his radio on. "All teams, ready on my mark?"
"Affirmative."
"Copy that."
"Remember, Agent Eppes may be in here. Our primary goal is to find him and get him out alive," said David. "Let's go. Move, move, move."
Three teams sprang into action simultaneously. David and Colby crashed through the front door, kicking it down as they went. Surprised, two men inside jumped up from their chairs, knocking a couple of half-full beer cans to the floor before running toward the other end of the building. A third whipped out a handgun and started shooting. Both agents fired back, and the shooter went down.
The SWAT team from the side entrance made their way into the room, confronting the two runners and quickly had them on the ground in cuffs. A man from the second SWAT team walked out from a narrow corridor leading from the back.
A call came from David's radio. "SWAT team two reporting all clear. One suspect in custody, back hallway."
"Copy that," said David. "One suspect down here, two in custody. All clear. Any sign of Agent Eppes back there?"
"Not exactly, but there's something you should see here."
David and Colby rushed to the back, leaving SWAT to watch over the suspects.
A narrow, dank hallway connected the larger room to the back room. In front of the doorway to the back room was a male suspect face-down on the floor in cuffs with a SWAT man standing over him. Colby walked past, into the room. It was filled with stacks of cardboard boxes. As he rounded one stack, he saw the SWAT team leader kneeling next to a chair.
"What have you got?" Colby said.
"It definitely looks like someone was held here. I can't say if it was Agent Eppes, though."
"Let me see."
Colby knelt down to examine the evidence. A pair of handcuffs lay on the ground, along with two zip ties, fastened and cut in half. Pulling on a glove, Colby picked up the handcuffs.
"These are law-enforcement issue. They could be Don's. The kidnapper didn't leave his at the scene," Colby said. "Have the suspects said anything yet?"
"Nothing so far, but I think your partner's working on it," said the SWAT man.
Colby looked up to see David speaking quietly—but from the look of it, not with gentle words—to the suspect, who was now standing up. He walked over as David signaled for SWAT to take the man into custody.
"Did you get anything?" Colby asked.
"The guy swears there was a prisoner in there—white with dark hair, medium height, wearing a black t-shirt and jeans. It could be Don," said David. "But it could easily be someone else."
"So where is he?"
"Suspect said that he last saw the prisoner around 7 p.m. to—" David gritted his teeth. "To give him some drugged water to make it easier to move him to another location tonight."
Colby looked at his watch. "That was only four hours ago. What happened?"
"Our perp swears he doesn't know. SWAT thinks he seemed just as surprised as us when they busted through the door to find Don gone."
"Could Don have escaped?" asked Colby, raising his eyebrows.
"I want to think so, but how? They drugged Don, and this guy's been on guard duty outside the door the whole time, and the only other way out I see is there."
David pointed to a small window near the ceiling, and Colby turned to look.
"Are you thinking what I'm thinking?" asked Colby with a tight smile.
"Let's call Charlie."