In the week preceding 20-23 October 2014 (see
here,
here and
here) several Prosecution witnesses testified about jammers in the motorcade, blocking transmissions by cell phones by emitting signals that block electronic devices that may be used to set off bombs. And again on 12 December another witness testified about the jamming systems.
Three of the cars of the former Prime Minister's motorcade had jammers installed. The witnesses all testify that at the beginning of each trip they made with Mr. Hariri, they would turn on the jammers and verify whether they were operational. If their cell phones or car radios were still operational, the jammer would not have been properly turned on.
The Prosecution's case seems to be that, given that all cars in the convoy contained such jamming devices, the bomb killing the former Prime Minister could not have been set off by a remote electronic device. The defence has cast doubt on this theory by revealing evidence from some of the Prosecution witnesses that at least one of the jammers was not functioning properly, thus allowing for an alternative assassination theory.
The week of 20-23 October saw two further witnesses testify about the technology of electronic countermeasures.
On 20th and 21st October, witness PRH507 testified under protective measures. This person has been working in the field of electronic countermeasures, more specifically, jammers and he delivered the jamming systems for Mr. Hariri's convoy. He explains that a jammer works within a specified band of frequencies within which it distributes signals that prevent receivers from communicating with the transmitters that belong to them. The transmitters cannot reach the receivers anymore, because the signal is being blocked.
Witness PRH507 inspected the jammers in three of the vehicles in January 2005, one month before the assassination, and they were functioning properly at that time. He further speaks about the impact of weather conditions on the functioning of the systems. The witness is also asked about the possibility of someone having used a satellite telephone to set off the bomb; the witness explains that topographically, Beirut is a complicated city, and using a satellite telephone for such purpose would be difficult.
After the explosion, the jammers were examined at the Beirut police headquarters; all of the switches were in "on" position (though one was completely destroyed). Also the jammer in the fifth convoy vehicle was switched on. However, the antenna cables were violently torn out of the plugs, and the witness indicates that this is strange. It is impossible to know whether they had been working at the time of the explosion.
At the end of the first day of his testimony, cross-examination of this witness commenced, and continued into the next day. The witness was presented three different possibilities regarding the setting off of the bomb, and asked to comment upon those. The first concerns the theory of a suicide bomber who receives a call, and he can see the convoy and then triggers the detonation. In the second theory there is no suicide bomber, but a timer that receives a call from a transmitter via a relay post. The call is logged before the jammers turn up, and a few seconds later the bomb goes off. The witness says these two theories are feasible. The third theory, however, he does not find feasible. In this theory, a phone connected to a transmitter is hanged up by a person, and that hanging up triggers the bomb to go off. The witness indicates that the act of hanging up on the part of the transmitter becomes more unlikely the closer the convoy gets to the recipient. The witness says that he has never seen a device that triggers the detonation of a bomb through the mere act of hanging up, though he concedes such device may exist.
The witness then testifies about the second car in the convoy, and how they found that several of the cables had been professionally deinstalled, while others had been ripped out by sheer brute force, and the witness adds that "[i]t's difficult to imagine that it could have been caused by the explosion". He also tells the court that the control light of the jammers would have still been on in the second convoy car, in spite of them not being operational given that the linking equipment to the antennae was disassembled or cut, though they would control the device by checking their mobile phones which would have warned them of the mechanical problem.
The witness is confronted with a statement from another witness who worked close to the place of the assassination. The latter witness testifies that she was watching television when the convoy of Mr. Hariri passed by. Normally, the jammers would affect her television, but on this particular day, the television was not affected. Witness PRH507 indicated in response that normally, one would conclude from this that the jammers were switched off.
The subsequent Prosecution witness PRH256, testifying on 22 and shortly 23 October, was one of the drivers for the Hariri family. Normally he would drive the former Prime Minister around in Lebanon, but on occasion they would travel abroad. The witness was in charge of activating the jammers in his vehicle, and they were constantly turned on. On the particular day, 14 February 2005, the witness drove the ambulance that followed Mr. Hariri's convoy. During the route, the radio was turned on, though it was interrupted once or twice. Normally, he would drive at a distance behind the other vehicles. In case of an explosion, the ambulance and people driving it must be safe. He is asked extensively about the distance of his vehicle to the convoy itself, but the witness states he no longer remembers this precisely, though stresses it would be no more than 15 metres. However, in a previous statement, the witness had indicated that when driving 50 metres away from the convoy, they would be able to listen to the radio.
In a previous statement to the UN investigation commission, the witness had indicated he thought the convoy had been followed by a suspicious car, an Opel Senator car, though he didn't consider it a threat at the time.
On 12 December, Mr. Diab testified by video-link from the office in Beirut about jammers in Mr. Hariri's motorcade. The witness worked for the Hariri family as an electronic technician, working specifically on the jamming system in the cars of the motorcade. Mr. Diab was in charge of the security equipment an systems, and, besides his colleague witness PRH507 (mentioned above), he was the only person who was allowed to touch the jamming devices.
Mr. Diab, his colleague witness PRH507, Mr. Hariri himself and Mr Yahya El-Arab's head of security knew their specifications. Two days prior to the attack, on 12 February 2005, the systems were checked by the bodyguards, and Mr. Diab testifies that it functioned properly, for if it hadn't, the bodyguards would have informed him. The witness further indicates that even if one of the jamming systems was turned off, the other two would still work. The jammers sent strong signals in forward directions, and weaker signals behind. The last car in the convoy was the ambulance, as indeed testified by many other witnesses before. The witness testifies that it would have been difficult to tamper with the jamming system. Mr. Diab further testified that the cars in the convoy could use radios amongst themselves, although that depended where they were.