and indicated the visitor. She rose from her chair and walked to Brix’s side.
“This is Amanda Sinclair from AirCom Consulting. Amanda’s here to explain text messaging, and give us a handle on how we can track, and hopefully apprehend, the UNSUB next time he contacts Karen.” He moved toward his seat. “Amanda.”
The woman, early thirties with frosted brown hair, took the center stage. “I know you’ve all used text messaging, or what we in the industry call SMS, or Short Messaging System. We don’t think much about those little notes we send each other. But they can be useful in law enforcement if we know how to use them. And if the criminal doesn’t. I think it’s important for you to know what we can’t do, as well as what we can do.
“So here’s the crash course. And I’m leaving a lot out, so if you’ve got a question, don’t be afraid to ask.” She opened a file and set out some papers. “The texts that go through a wireless provider’s system are not viewed by the carrier. They don’t read them—they simply store the technical transmission information for varying periods of time. Very few carriers actually store the ‘text’ of text messages. The storage space required, multiplied by the billions of texts exchanged between users, is staggering.”
“How long do they keep this transmission information?” Lugo asked.
“Good question. The answer depends on the carrier. Basically, there are several different systems for storing message information. The two most common are CDR and SMS Center. In CDR, or Call Delivery Records, the information is stored for seven days. These CDRs list information such as the time stamp—year, month, day, hour, minute, second, character length—and a variety of other technical info. The International Mobile Subscriber Identity, or IMSI, is also stored; it’s like a thumbprint for the SIM card that houses all the phone’s user specific information. You all know what a SIM card is, right? It’s a little flash memory chip that fits into certain phones. You pull the card out of your old phone, slip it into a new one, and you’re ready to go, without having to reenter all your contacts and such. With me so far?”
“Go on,” Brix said.
“We also store the IMEI, or International Mobile Equipment Identity, a unique thumbprint for the exact phone equipment that’s used. But it’s got no permanent relationship to the individual subscriber. It’s mainly used to identify valid users of the network, so if the phone is stolen, the carrier can shut off that IMEI and the phone will be a useless hunk of metal and plastic.
“The other commonly used system is the SMS Center, which is the E.164 address that lets everyone know which carrier the SMS is originating from or terminating to, the phone number the message is being sent to, how the digits were dialed, and so on. Here’s an example.” She moved to the overhead projector, set one of her pages on top, and turned it on. A document that resembled an Excel spreadsheet was displayed. A bar at the top read, SMS Center Log Window.
Everyone studied the screen. Vail and Lugo were taking notes as Amanda oriented the task force members as to what they were seeing.
“Any questions?” she asked.
“You said there are other ways of storing messages,” Lugo said.
“Yes. Another common method is called SMSC, or Short Message Service Center. It shows where the messages originate and terminate from a carrier’s system. This info is kept for a period of time based on message capacity. Sometimes, if there’s a lot of messages, they’ll only have the data for a week. Other times they may be able to go back a month.”
Amanda slipped a different page onto the projector, showing a gray table with eleven columns aligned horizontally across the document. “The SMSC printout shows the millisecond messages are submitted from the handset and delivered out of the SMSC to the other carrier. It also shows the destination phone number. Now, it gets more complicated, because some carriers have third party vendors that send their intercarrier traffic for them.”
Agbayani pointed at the screen. “Can we use this to determine the location of a perp who’s transmitting a text message in real time?”
“Yes. If the carrier uses GSM technology, you can triangulate within a seven-to twenty-mile radius.”
“Miles?” Lugo tossed down his pen. “You’ve gotta be kidding.”
“Point is,” Brix said, “we can determine the type of phone used and where he may’ve bought it.”
“That
Gordon rocked forward in his seat. “I think we should plot the messages the asshole’s already sent to Vail and set it up so we’re monitoring her cell in real time. If and when this scumbag texts her again, we can at least triangulate on him.” He spread his thick hands. “Better than nothing.”
Amanda said, “Not to make things more difficult for you, but one thing you should be aware of is that the texts sent to Agent Vail’s phone were from different disposable, pre-paid phones.”
Mann slowly shook his head. “I think Ray’s right. Waste of time.”
Brix sighed. “Look, we do what we’ve gotta do. We use the tools available to us. Anyone got a better idea, now’s the time.”
Everyone looked at one another.
Dixon thanked Amanda for her assistance and dismissed her. She then recapped the information she and Vail had learned from Crystal Dahlia, Ian Wirth, and Robert Friedberg. “Karen’s still got a problem with the motive because it just doesn’t fit with how serial killers operate, their whole psychological makeup, and why they do what they do. But I think we should follow the course, see what we turn up.”
“We’re always learning and seeing new things,” Vail said. “So this offender could be a new breed, or just something we haven’t seen before. Right now, I wouldn’t discount anything. I wish I could offer more, but I’ve had a hard time putting it all together.”
“Let’s have you guys stay on it, dig deeper into the AVA board and its players,” Dixon said. “Karen and I have a follow-on appointment in half an hour with the attorney. We’ll keep you posted.”
Brix opened his notepad and flipped pages. “Last order of business. I’ve got something from the Special Investigations Bureau on the prosthesis request Karen had.” He shot a glance at Mann, then Vail, and continued: “This is preliminary stuff, but there were a total of a hundred-fifty-seven males with upper limb prosthetics. Only eleven in the age range Karen specified. Two were alibied, three were out of town and unreachable and the other six are being interviewed, or are scheduled to be interviewed. Just going by their sheets and backgrounds, it doesn’t look promising. But I told NSIB to ride it out. Questions?”
No one spoke.
“Okay, then. Keep at it. You find anything, let us all know.”
“You’re in for a real treat,” Dixon said. “Artesa has one of the more picturesque views of the valley. And judging by the weather and rainfall we had last month, you’re going to get an eyeful.”
Dixon took Highway 121, then turned left onto 12.
“Isn’t this the same way we went to Sonoma?”
“It is. But not nearly as far. We’re gonna turn off 12 in a few minutes, into the Carneros Region. Carneros is known for its Pinot Noir and Chardonnay. But Artesa is one of my favorite places to take guests when they come to visit. It’s like an art museum rolled into a winery.”
Dixon drove up the curving driveway and parked in the visitor’s lot. “We’re early. Let me take you the long way around, show you the view.”
As they walked along the path from the car, they came to a large circular pond with a fountain shaped like a short martini glass. Water cascaded over the edges and landed in the surrounding pool. Large, glistening, silver railroad-spike-shaped sculptures stood erect along its periphery.
“What are those things sticking up?” Vail asked.
“Hell if I know. They’re cool looking, that’s for sure.”
Beyond, the vineyard-blanketed rolling hills stretched for miles in all directions.
