Lebanese military intelligence held on Thursday a number of people for their testimony and narrow down suspects in the attack on the United Nations Interim Force in Lebanon (UNIFIL) last week that left an Irish peacekeeper dead. Pvt. Seán Rooney, 23, was killed and three others wounded when their unidentified attackers opened fire on their convoy as it passed near the outhern town of Al-Aqbiya. The area is a stronghold of the Hezbollah party. Pvt. Shane Kearney, 22, was left in serious but stable condition and has since been flown back to his home country for further medical treatment. Security sources told Asharq Al-Awsat that the probe has not yet determined whether the detainees are directly complicit in the attack. The probe is still in its early stages, they added. Authorities have obtained footage from surveillance cameras that were in the area, they revealed. Investigators have identified suspects, a judicial official told AFP on Thursday. "The investigation has been able to identify suspects but so far none has been arrested and the security services are still looking for them," said the judicial official who could not be further identified. The UN patrol "was the target of gunfire from at least two people" when it arrived in Al-Aqbiya, according to the same source. Citing preliminary findings, the source said the incident "was premeditated and the patrol was surveilled and followed by a car carrying armed men". UNIFIL acts as a buffer between Lebanon and Israel, neighbors which remain technically at war. The force operates near the southern border. Wafiq Safa, Hezbollah's security chief, has said the killing was "unintentional". Witnesses said villagers in the Al-Aqbiya area blocked Rooney's vehicle after it took a road along the Mediterranean coast not normally used by UNIFIL. Al-Aqbiya is just outside UNIFIL's area of operations, the force said. A Lebanese judicial source earlier told AFP that the driver was killed by a bullet to the head, one of seven that penetrated the vehicle. The three passengers were injured when the vehicle hit a pylon and overturned. According to the judicial official, the patrol was "harassed and intercepted at two locations before reaching the scene of the incident". The official said, without elaboration, that there had been "difficulties linked to the investigation" but interviews with civilian witnesses led to the suspects' identification. UNIFIL was set up in 1978 to monitor the withdrawal of Israeli forces after they invaded Lebanon in reprisal for a Palestinian attack. Israel withdrew from south Lebanon in 2000 but fought a devastating 2006 war with Hezbollah. UNIFIL was then beefed up to oversee a subsequent ceasefire and now counts more than 10,000 soldiers and naval personnel. Last week, the mission urged Beirut to ensure a swift investigation into the first death of a UNIFIL member during a violent incident for nearly eight years.