Lebanon News

STL: Accuracy of cellphone-coverage maps contested

BEIRUT: Special Tribunal for Lebanon defense counselor Chad Mair cross-examined expert witness John Edward Philips throughout Tuesday’s hearing, focusing on anomalies in cellular coverage maps and questioning testimonies made based on unclear data. Cellular evidence has been critical for both the prosecution and the defense, as the five indicted suspects accused of carrying out the 2005 Beirut bombing that assassinated former Prime Minister Rafik Hariri and killed 21 others are currently undergoing trial in absentia.

Mair, representing the interests of defendant Salim Ayyash, spent the majority of Tuesday’s session highlighting inconsistencies in original data provided by Lebanese cellular network company MTC touch. The data was then used to create cellular coverage maps, which the prosecution has previously used to track the movements of the five accused.

In particular, Mair focused on a phone call made by a cellphone attributed to an unnamed defendant in the southern governorate of Nabatieh. While Philips’ expertise led him to believe that “Nabatieh C” area was the accurate cell attribution in the case of this call, cellular coverage maps pointed instead to “Nabatieh D” site.

“Nabatieh C was the best serving cell [area covered by the local tower] ... If they drove the other way they may initially find that Nabatieh D is the best serving cell,” Philips said. “But the findings [leading to Nabatieh D] are from MTC, and I’m not about to disagree with them.”

The expert witness, who has been named the prosecution’s principal expert in cellular sites, admitted that MTC touch was not able to give proper explanations for inconsistencies in the original data used in the creation of the cellular coverage maps used in the trial.

“I don’t think what they’ve shown [us] is the complete answer, and I don’t think it’s consistent. They said they were experiencing 2G problems, and I’m not exactly sure what that means,” Philips said.

The defense has pushed that the second-best practice would be to cross-check the maps against the reality on the ground. Philips said much the same, noting that the best way to double-check coverage would be “if there is a drive test and field survey done to compare the best predicted coverage plot to what’s going on in reality.”

But it was revealed Tuesday that Philips had not traveled to Lebanon during the initial STL investigations.

The expert witness admitted that his last visit took place in the ’70s, before cellular phones were in use, thereby rendering him unable to give “on-the-ground” testimony on Lebanese cellular networks.

During last month’s cross-examination of expert witness Gary Platt – another covert cellular networks specialist – defense counselor Vincent Courcelle-Labrousse similarly found that Platt could not confirm the accuracy of cellular coverage maps.

At the time, Courcelle-Labrousse, representing the interests of Hussein Oneissi, claimed the maps could be up to “30 or 40 percent inaccurate.”

 
A version of this article appeared in the print edition of The Daily Star on April 26, 2017, on page 3.

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