A Crossover between Numb3rs and the Mentalist.
Warning: Mentions of Math
Dedicated to JLM110108, because she wrote a Numb3rs/Are You Smarter than a Fifth Grader story for me.
The blind date was going exceptionally well, Teresa Lisbon thought. At least, they had managed to get all the way to dinner without the dark haired CBI agent feeling the need to a) shoot herself, b) shoot her date or even c) shooting the people who had set them up.
Going for a whole day without once wanting to shoot Patrick Jane was definitely worth blogging about.
Colby Granger had taken her to a chain restaurant. Not the fanciest place around, however, The Olive Garden did serve edible Italian food that was passably authentic. On top of that, Colby was good-looking, personable and intelligent. Granted, he was younger than she was, but not enough to make her feel like a cougar.
Besides, that minor defect was more than made up for by the fact he did not fuss about them being interrupted by her cell phone, not even when it happened for the third time.
"Do you need a doggie bag, Teresa?" he asked when she returned to her seat.
Teresa shook her head. "No, what I need is to get in touch with my genius consultant," she sighed.
"Rough case?" Colby asked sympathetically.
"I've had worse," Teresa admitted. "But this one is getting on my nerves in a major way."
"Care to talk about it?" Colby asked. The blond FBI agent put his right hand over his heart and held up his left, as if to swear to his pure intentions. "I promise I won't try to steal credit for the bust from the California Bureau of Investigation."
Teresa laughed. "Okay, since you insist," she waited for the waiter to deposit another basket of bread sticks and leave before she continued. "It's actually a pretty straight-forward case." She paused. "Well, as straight-forward as these cases ever get."
Colby nodded and helped himself to a bread stick. Teresa looked at them a bit wistfully, but they were far too salty for her.
"It's a series of burglaries through several counties," she shrugged. "Which is why we were called in."
"Because none of county sheriffs and the city police have jurisdiction over the others, and it's easier to call in the big dogs rather than figure out a way to co-operate?" Colby suggested.
Teresa let out a woof of laughter. "Well, that and the fact that a task force takes time and money to organize and these robberies don't seem important enough to warrant that sort of action."
Colby nodded. "So, where are the robberies?"
Teresa spread her hands to indicate a lot of territory. "Here in LA, in Orange County, Santa Barbara County, Surf County... What?"
Colby made an effort to remove the frown from his face. "Sorry, I just thought that I knew all the counties near LA. Surf's a new one on me."
Teresa felt herself smiling. "Surf County is relatively small. Except for the county seat, it's all rural; farms, ranches, houses set on an acre or more of land."
"Wow, maybe they should change the name to Surf'n'Turf County," Colby said.
"And it's how far from Los Angeles?" Colby asked.
"About forty-five minutes," Teresa replied, falling into the Angeleno custom of measuring distance by how long it takes to get someplace rather than in mere miles. "The really odd thing is... no freeways."
Colby feigned shock. Well, mostly feigned shock. "Really? How do people get there, horseback?"
Teresa grinned again. "Surface streets, my man, including Pacific Coast Highway."
"Wow, I wonder how long the developers are going to let that go on," Colby murmured, only half in jest.
Teresa shrugged. "I can't do anything about that," she said. "However, I should be able to do something about the break-ins."
"Sounds like Surf County would be the hardest cases to crack," Colby murmured. "Doesn't sound like there would be many witnesses, what with the houses set so far apart."
Teresa grimaced. "Oddly enough, our only witness is in Surf County."
"No other leads?" Colby asked.
Teresa shook her head. "We have trace, but nothing definitive. We have some DNA samples from the times when one of the burglars cut himself or stopped to snack on some fresh brownies."
"They ate some brownies at the scene?" Colby asked incredulously, although he had to know that many criminals were stupid and/or arrogant enough to do such a thing.
Teresa nodded. "Actually, they made themselves snacks at several of the burglary sites, and they made off with a lot of food, cookies, cake, coffee, a five pound box of See's Candies..."
Colby shook his head. "Criminals never cease to amaze me," he admitted. He straightened up as their food arrived. The waiter put Teresa's Eggplant Parmigiana in front of her and Colby's Pork Filettino in front of them, offered extra Parmesan cheese and then faded into the woodwork.
Teresa would have really liked a glass of wine with her dinner, but she was almost certain that she'd be going back on duty before the night was over. A pity, because Colby had turned out to be a true gentleman.
"No hits on the DNA, I presume?" Colby asked.
"You are correct, sir," Teresa responded. "What we have is a witness, who saw a man leave one of the Surf County crime scenes and get into a taxi."
"That's so unusual in California," Colby murmured.
Teresa decided to forgive the snark as he'd been a good date so far. "Actually, it's significant because the man got into the driver's seat."
Colby sat up a little straighter. "Really? So the taxi driver is a person of interest?"
Teresa nodded. "It makes sense, most of the robberies have taken place after the owner has been dropped off at an airport, or a train station."
"Ah, so, I'm assuming that questioning the cab drivers hasn't yielded any useful information?"
Teresa grimaced again. "Well, there's another problem. We aren't one hundred percent certain about the cab company. We're hoping that it's a genuine company, because if it's fake..."
"Then you're in trouble," Colby said.
Teresa made a face at him. "Funny." She took a few moments to savor her dinner before continuing. "It's not as bad as it could be," she continued. "There are only two cab companies that are licensed to operate in Surf County."
Now it was Colby's turn to make a face. "Laws governing California cab companies are almost as bad as the tax laws."
"Tell me about it," Teresa said. "I've never been in a county outside of Los Angeles where it's illegal for a cabbie to pick somebody up off the street."
"And where each city insists on having a separate hack license," Colby added. "Makes it hard to go from one city to another."
"But maybe easier to locate our suspect in this robbery," Teresa sighed. "As I said, there are only two legal cab companies in Surf County, Blue and Green. The witness insists that he saw a Blue Cab."
"I'd think that would be pretty definite," Colby said.
"Thing is, the sighting was at night."
"Dang," Colby said.
"However, the area was well lighted and we tested the witness' accuracy by going back to the scene of the crime and running cabs past him. He correctly identified four out of five, so we figure that there's an eighty percent chance that a blue cabbie is our guy. So my guys are checking them all out."
Just then, her cell phone shrilled.
She pulled it out, looked at Colby, who shrugged, and then she answered. "Lisbon," she said. "Damn, he would pick tonight to turn his cell phone off. Okay, Cho, talk to them all again." She shut her cell phone off and sighed.
"Someone disappeared on you?" Colby asked.
Teresa looked at him blankly as she ran her last conversation through her mind. "Oh, Patrick Jane, my genius consultant, is off on vacation," she said. "He warned us that he'd be out of touch."
"Well, maybe my genius consultant... my team's genius consultant, that is... can help," Colby said. "He's helped in some surprising ways."
"My budget won't run to another genius consultant," Teresa said.
"Well, we can at least ask and see if he thinks he could help. Maybe he'll give you a government discount." Colby replied. His Pork Filettino was getting cold on her behalf, so Teresa decided to go along with his plan.
"Sure," she said.
Colby pulled out his cell and punched in some numbers. Teresa wasn't surprised that his cell was on. She was, however, a bit surprised when she realized that the Genius Consultant was on speed dial.
She thought she was the only one who did that.
"Charlie, hey, it's Colby, am I interrupting something?" Colby paused. "Oh, good, I've got a question that I'm not sure you can help with... No, it's not a case for the FBI."
He paused again. "It's actually for the CBI, if you must know... No, not Rachel, it's a woman that Rachel and some friend of hers set me up with. Well, so far it's going pretty good, only we made the mistake of falling into some shop talk."
"Okay, here's the deal. Two cab companies, green and blue, right?" Colby nodded to himself. "Well, there's a witness who can, with eighty percent reliability place a blue cab at the scene of the crime..."
He rolled his eyes at Teresa and grinned. "Well, it was at night." He paused. "Well, her team tested the witness at the scene of the crime under the same lighting. He was able to correctly identify the color of the cab four out of five times. That's eighty percent, right... No?"
Colby shot Teresa a confused look.
Teresa's eyebrows went up. "What are we missing, then?" she asked.
Colby repeated the question. He frowned. "Prior odds? What do you mean?" He looked at Teresa. "He needs to know what were the odds of the cab being blue were to begin with."
Teresa blinked. She fished her notes out of her purse and flipped through them. "Um, there are thirty cabs in the green fleet, seven in the blue fleet. Some of them were definitely accounted for... So, consider that there are twenty-five green cabs and five blue cabs."
She cocked her head at Colby's cell phone.
Colby repeated the numbers to Charlie and added, with a puzzled look on his face, "So, how does that change the odds? Wait, explain to Agent Lisbon." He handed her the phone. "Professor Charlie Eppes, Agent Teresa Lisbon."
"Hello, Professor," Teresa said. "I've read some of your papers on Bayesian statistics and I'm guessing that's what this is about."
Charlie Eppes had a pleasant, raspy voice. "Yes. That's exactly it," he said, sounding pleased. "Well, you need to account for what the prior probability of which color cab was at the site of the crime."
Teresa nodded. "Okayy... How do we do that?"
"Well, ignoring the witness for a moment, what were the odds that the cab at the scene was blue?"
"Um," Teresa said. She looked at her notebook.
Colby handed her a pen and she calculated in the margin. "Twenty-five green versus five blue... that's five to one..." she hesitated. "Or should I say one to five?"
"Right," Professor Eppes said. "Now we have to calculate the odds. We need to divide the odds of A being true (given X) divided by the odds of B being true (given X) and multiply that by the Likelihood Ratio."
"The what?" Teresa asked feeling like she was in high school again.
Colby began to look worried.
"The Likelihood Ratio is the likelihood of observing X if A is true divided by the likelihood of observing X if B is true."
Teresa blinked. "Ohhh... kay."
"Right," Professor Eppes said, apparently sensing he was losing his audience. "Okay, look at it this way. Suppose all thirty cabs go out one night. The witness sees them all under the same lighting as the night of the crime."
"Okay, I'm following you," Teresa said feeling relieved.
"Given his success ratio and the ration of green cabs to blue cabs, he'll describe four of the blue cabs as being blue and one as being green. But then he'll describe five of the green cabs as being blue. So... he'll report seeing nine blue cabs when he actually only saw four."
"That's not an eighty percent success rate, is it?" Lisbon sighed.
"No, that's forty-four percent," Eppes said. He hesitated. "I hope that helps."
"Well, it gives us a new tree to bark up," Lisbon said. The waiter pushing a dessert tray passed their table. "I mean, it gives my team some new trees to bark up," she said. "I think I'm going to finish my dinner and then have some tiramisu."
"Bon appetit," Professor Eppes said.
"Thank you, Professor," Teresa replied. She hung up and handed Colby his cell phone. "And thank you."
Colby swallowed his luke warm Pork Filettino. "Any time," he said with a smile.
Teresa called Kimball Cho. "Forget the Blue Cab company for now," she said. "Focus on the Green. Odds are, it was one of their cabs the witness actually saw... Do you want me to explain Bayesian Filters to you? I didn't think so. Yes, there doesn't seem to be a rush on this. Tomorrow will be fine, Cho. Enjoy the Kings game."
She hung up and, after due consideration (five seconds) she shut the power off.
Colby laughed and shut his cell phone off, too. "I think we can afford to eat our tiramisu in peace," he said.
"I'll drink to that," Teresa said. She lifted her water glass and touched it to Colby's.