A representative of the Alfa cellular network Thursday detailed his company’s evolving infrastructure to the Special Tribunal for Lebanon, illustrating the difficulties faced by investigators as they try to piece together call-data records in support of their case. The tribunal is interested in the location and configuration of Alfa’s cell sites as they existed in 2004 and 2005, during the period prosecutors claim they were able to identify and track the defendants as they plotted the assassination of former Prime Minister Rafik Hariri.
Alfa is one of only two networks operating in Lebanon, and though it has turned over reams of billing records and reprocessed call data to prosecutors, archives on its cell sites are less complete. Cell sites each contain a number of antennas, oriented to provide coverage in concert with the network’s other towers. The orientation, or azimuth, of each antenna is adjusted to this end. Cellphones typically connect with a specific coverage area broadcast from the nearest tower, so understanding the delineation of these areas is vital for accurately locating users.
According to the witness, Alfa does not have contemporary records on the locations of its cell sites or the respective azimuths of their antennas from 2004-05, so their exact values are impossible to confirm. Its earliest data is from 2007, and it has attempted to extrapolate back from there. Furthermore, though the witness was purportedly selected to represent the company due to his familiarity with the network, much of his testimony has relied on company records, whose accuracy he could not personally confirm.
The defense’s Eugene O’Sullivan challenged the admission of certain Alfa records tendered as evidence. “The witness has said multiple times, ‘The accuracy of certain numbers in this file is impossible to be confirmed,’ therefore it cannot be considered probative or relevant to this case.”
Given the absence of the applicable data, prosecutors have tried to demonstrate that whatever the exact positions of the antennas at the time, any difference from the 2007 configurations would be immaterial given the manner in which the network was configured and maintained. They presented records documenting the generally minor changes recorded since 2007.
“A radical change in the tilt of the antenna to solve a problem is not a method that we adopt, because that would cause other problems,” the witness testified. But he added that the network can change the direction of the antenna if a new cell site is constructed nearby, and minor adjustments are sometimes made to address specific complaints about coverage.
The witness detailed other factors that can affect coverage and cell siting as well, including weather, illegal use of frequencies, regional conflict and incidents of what he believed to be intentional jamming of the system. One of Alfa’s mobile cell sites was reportedly damaged in the bombing of Hariri’s convoy on Feb. 14, 2015, knocking it out of service for several hours. The defense has put forward all of these scenarios in questioning the reliability of the evidence.
But throughout his testimony the witness asserted that the operation of the network in 2005, from cell-site installation to repair times, would be in line with industry practices, and that it was fair to make certain assumptions about how it worked.
“Currently, as an operator of mobile phones, we try to limit the time of any station going out of service because this will lead to financial losses, the complaints will increase and the image of the company to its subscribers will be damaged. ... I think that in all other years the same trend existed.” The tribunal is scheduled to hear further testimony from the Alfa representative Friday.