A French judge and prosecutor are to travel to the UK as part of an investigation into the murder of a family in the Alps.
They will join a small team of French investigators already in Britain to help find out what led to the shooting of engineer Saad al-Hilli, his wife and mother-in-law, as well as a French cyclist, near Lake Annecy a week ago.
Meanwhile, three more people were found in a car following a shooting on the French island of Corsica on Tuesday, although there was no immediate evidence of any link.
A witness who came upon the aftermath of the Alps massacre likened the carnage to a horrific film scene.
The man, named only as Philippe D, 41, a hiker, told Le Parisien newspaper how he came across the dramatic scene after setting out with two female friends to go walking. He recalled how the group was met by a "panic-stricken" British cyclist making his way down from the murder scene as they drove up a hill in the Combe d'Ire forest, near Chevaline.
Arriving at the car park, Mr D saw the bodies of Mr al-Hilli, 50, his dentist wife Iqbal and Mrs al-Hilli's mother in their bullet-ridden BMW. A fourth body, that of Sylvain Mollier, 45, the French cyclist who apparently stumbled across the attack, lay on the ground. Zainab, seven, was lying by the car.
The walker said they had seen no one as they drove up through the forest and that the killer or killers could have escaped using a winding lane which leads directly to the motorway.
He spoke out as it emerged the al-Hilli family had moved from one campsite to another two days before they were gunned down. A Dutch couple believed the group planned to spend a week at the three-star Village Camping Europa site in St Jorioz after they arrived last Saturday, but they left on Monday. The family were staying in a caravan at neighbouring campsite Le Solitaire du Lac when the killings happened.
Sources said the victims were likely to have been blasted with the same gun, fuelling speculation they were targeted by a contract killer. Each person was shot twice in the head. Detailed ballistic analysis of 25 spent cartridges found at the scene suggests they all came from a 7.65mm automatic pistol. But Annecy's public prosecutor Eric Maillaud has denied confirming this detail.
Zainab, who was shot and so brutally beaten that doctors placed her in a medically induced coma, is now seen as one of the key witnesses. Police spoke briefly with her after she regained consciousness on Sunday and are waiting for approval from medics before they can question her further. Her younger sister Zeena, four, escaped unscathed by cowering behind her mother as bullets rained down. She has flown back to Britain with carers.