“I’ve been a special agent with the FBI for almost eleven years,” he tells Ogren. “I’ve been assigned to our Narcotics and Firearms Task Force for the last five.”
“As part of your duties, do you analyze cell phone records?”
“Yes, that’s the largest part of what I do these days. I typically do historical cell site analyses on cell phone records.”
“Why do you conduct historical cell site analyses, Agent Jumer?”
“The purpose is to determine the approximate locations of cell phones at the time the calls were placed that are detailed in the records.”
A cell phone is a radio, and when it’s used it sends out radio frequencies in all directions. It will hit multiple towers belonging to that service provider, and that provider will have a switching channel that will pick which of its towers should provide service to the cell phone. Each tower has its own identifier, and the service provider records that particular tower in its call detail records.
So when you call somebody on a cell, the FBI can go back later and say, at this day and time, you initiated a phone call, and this was the tower that provided service to that phone. The tower providing service is usually the one that’s closest to the cell phone’s location, but not always, especially in an urban area with high call traffic. So it’s not an exact science.
If this were an area of contention with us, we’d have some basis to go after this witness. In fact, as a defense lawyer, I once had Dennis Jumer on the stand for half a day, berating the FBI’s methodology and criticizing them for not using triangulation or GPS, which are more accurate. I assume that Jumer remembers that day, and me.
Agent Jumer talks for a while about his credentials and experience; then he turns to the details of this case. He was brought in by the county attorney’s office to analyze the cell phone records of Alexa Himmel and me for the week preceding her murder.
“We obtained the records, by subpoena, from Ms. Himmel’s service provider and Mr. Kolarich’s service provider,” he says.
“People’s Eighteen, Judge. There was a stip on this.” Roger Ogren displays on the screen a summary chart of phone calls made by Alexa’s cell phone to my cell phone, or landline, or office, on the date of Friday, July 26.
Shauna nods to the judge. “It will be admitted,” says Judge Judy.
“Did you prepare this chart summary?” Ogren asks Jumer.
“I did.”
“Please tell the jury what it shows.”
“This chart shows calls made from Ms. Himmel’s cell phone to either Mr. Kolarich’s landline number, his cell phone number, or his direct line at his law firm, as well as the date and time of those calls, the length of time, and the cellular tower that originated the call. For privacy reasons, rather than using the actual phone numbers, we denoted Mr. Kolarich’s cell phone as ‘Kolarich Cell,’ his landline at home as ‘Kolarich Home,’ and his direct office line as ‘Kolarich Office.’”
“And is this chart limited in time, Agent?”
“Oh, yes, I’m sorry. Yes. This chart covers phone calls made by Ms. Himmel’s cell phone only for the date of Friday, July twenty-sixth of this year.”
“Just a one-day period?”
“Just a one-day period. Twenty-four hours. Just Friday, July twenty-sixth.”
The jury probably remembers the first e-mail from Alexa that was introduced into evidence, the Why won’t you return my calls? e-mail that was dated Saturday, July 27. They are about to see all of the calls that I wasn’t returning.
CALL DETAIL RECORDS FOR CELL PHONE OF ALEXA M. HIMMEL
Friday, July 26
Time
Destination
Length of Call (minutes)
Originating Cell Site
10:32 AM
Kolarich Cell
1
221529
2:47 PM
Kolarich Cell
1
221529
2:59 PM
Kolarich Cell
1
221529
3:12 PM
Kolarich Cell
1
221529
3:13 PM
Kolarich Office
1
221529
3:15 PM
Kolarich Cell
1
221529
3:58 PM
Kolarich Cell
1
221529
4:45 PM
Kolarich Cell
1
221529
5:22 PM
Kolarich Cell
1
221529
5:23 PM
Kolarich Cell
1
221529
7:02 PM
Kolarich Cell
1
221529
8:28 PM
Kolarich Cell
1
221529
8:29 PM
Kolarich Home
1
221529
8:31 PM
Kolarich Cell
1
221529
9:46 PM
Kolarich Cell
1
221529
10:37 PM
Kolarich Cell
1
221529
11:14 PM
Kolarich Cell
1
221529
11:17 PM
Kolarich Cell
1
221529
11:21 PM
Kolarich Cell
1
221529
11:25 PM
Kolarich Home
1
221529
11:27 PM
Kolarich Cell
1
221529
11:32 PM
Kolarich Home
1
221529
11:47 PM
Kolarich Cell
1
221529
11:49 PM
Kolarich Cell
1
221529
“That’s twenty-four phone calls,” says Jumer, when asked. “Twenty-four phone calls in a twenty-four-hour period. Really, a fourteen-hour period.”
“Agent,” says Roger Ogren, “I see that each of these calls says that their duration was one minute. Does that mean that each call was precisely sixty seconds?”
“No, obviously not,” Jumer replies. “This particular service provider-like all of them, I believe-charges you for a minute of time the moment a call is placed. So a ten-second call is charged as one minute. A fifty-nine-second call, charged as one minute. We are limited to what the service provider can give us, and they don’t go lower than one minute.”
“So does this mean that every call made from Ms. Himmel’s cell phone to one of Mr. Kolarich’s numbers was less than one minute?”
“Yes, it does. Sixty seconds or less.”
“Does the service provider differentiate, to your knowledge, between calls that are received by a live person and calls that are received by that person’s voice mail?”
“No, there’s no difference. All this computer knows is that the other line picked up.”
“So it’s possible that some or all of these calls made by Ms. Himmel went to voice mail.”
“It’s possible, sure. Common sense says it’s likely. But it’s impossible to know.”
“Fine, that’s fine.” Ogren clears his throat. He’s sounding a little nasal today, the onset of a cold. Trials can be murder on your health, though I usually didn’t get sick until after it was over, like my immune system knew when it was okay to surrender.
“Agent, the farthest-right column refers to the ‘originating cell site.’”
“Yes. That’s the tower that provided service to her call.”
“And did you estimate the range of coverage of that cell tower?” Ogren puts up a chart of a map of the city and the near-south suburbs, including Overton Ridge, where Alexa lived.
“Yes. This map shows the estimated range of coverage of cell tower number 221529,” he says.
The map has a large red triangle at the location of that cell tower. From that red triangle, a large yellow-shaded area fans out to the east, about a third of a circle, showing the estimate of the range covered by that cell tower.