Italian prosecutors probing the killing of Italy's ambassador to the Democratic Republic of Congo have opened a case against a local aid worker responsible for his security, reports said Thursday. Luca Attanasio, 43, his Italian bodyguard and a Congolese driver died following an ambush on February 22 against a World Food Programme (WFP) convoy travelling through a dangerous part of eastern DRC near the border with Rwanda. The identity of the perpetrators and the motive for the attack remain unclear. But the Rome prosecutors office is investigating a Congolese official of the Rome-based WFP responsible for the convoy's security, accusing him of failing to take the proper precautions, Italian media reported. According to La Repubblica newspaper, UN rules state that permission to enter dangerous territory must be sought from senior officials at least five days in advance, but the WFP official only made the request the evening before departure. He reportedly obtained last-minute authorisation by omitting to mention that the two Italians would be part of the convoy. Had he done so, there would likely have been greater scrutiny of the risks. According to Il Corriere della Sera newspaper, the WFP employee survived the attack and was an eyewitness. The WFP, a branch of the UN which focuses on hunger and food security, declined to comment to AFP on the reports. However a spokesman said that the WFP was cooperating with the investigations, "collaboration (which) has included the testimony, as witnesses, of staff who were present at that tragic event". "WFP hopes that the perpetrators of this heinous criminal act will swiftly be brought to justice," he said. The convoy was ambushed north of the North Kivu capital of Goma on a road that runs through thickly forested, mountainous terrain next to the porous border with Rwanda. It was attacked by six assailants armed with five AK-47 assault rifles and a machete. They shot dead the driver and forced the others into the forest. Park rangers and army troops nearby heard the noise and pursued the attackers, but the assailants shot the bodyguard on the spot. The ambassador was wounded and died later in hospital. In the wake of the attack, the DRC's interior ministry blamed the killings on the Democratic Forces for the Liberation of Rwanda (FDLR), a Rwandan Hutu rebel group. The FDLR rejected the allegation and instead blamed the Rwandan and DRC armies. ljm-ar/ams/dl