During cross-examination at the Special Tribunal for Lebanon Wednesday, defense counselor Chad Mair questioned expert witness John Edward Philips about his analysis of so-called co-located phones. The term, used throughout the trial, denotes instances in which multiple cellphones attributed to a single individual made calls from the same area of cellular network coverage within a short time period.
Throughout Philips’ testimony, instances of co-location have been used to support his “single user analysis” theory. This hypothesis, put forward by the prosecution, has been used by investigators throughout the case to demonstrate that multiple phones were likely used by the same person.
Cellular data, like the information analyzed by Philips over the course of the past week, has been integral to the prosecution’s case against the five defendants accused of planning and executing the 2005 bombing that assassinated former Prime Minister Rafik Hariri and killed 21 others.
Prosecutors have used the movement and coordination between various cellphones attributed to individuals and color-coded cell networks to track the alleged conspiracy leading up to the attack, as well as to identify the defendants in the case.
Consistent with previous cross-examinations by defense counselors, Mair’s line of questioning Wednesday attempted to compromise the integrity of Philips’ testimony.
Referencing analysis conducted by Philips that counted the number of times two phones attributed to the unnamed Subject 7 were co-located, Mair noted that over the course of a period of several months, co-location between the phones in question occurred only once.
“This would seem to run contrary to your statement that you need more than one example of potential co-location to conclude that there is a single user,” Mair said, addressing Philips.
The expert witness countered by noting that, in situations such as this where there may have been a clear attempt to keep various covert cellular networks separate, it would not be surprising for there to be relatively few instances of co-location.
In the past, the prosecution has alleged that different color-coded networks were used to carry out various stages of the plot and were often not in contact with each other.
“If you were really trying to isolate the red and blue phones, there should be no moment where they are co-located. Red phones were used on certain dates and days and during those periods it would appear that the use of blue phones was precluded,” Philips said.
Following the end of Mair’s cross-examination, Jad Khalil – defense counsel for Hassan Merhi – began his cross-examination.
Though his questioning will continue next week, Khalil’s initial inquiries focused on how the destruction of Beirut’s southern suburbs in the 2006 war with Israel may have affected the prosecution’s ability to effectively map cell coverage.