French and British police are conducting further searches at the home of Saad al-Hilli and his wife as detectives investigating the Alps killings prepare to interview the couple's relatives.
Officers began a detailed search of the family's mock Tudor property on Saturday as they seek to establish a motive for the murders that saw each of the four victims shot twice in the head.
Mr al-Hilli, 50, was killed in his car alongside his dentist wife, named by neighbours as Iqbal, on Wednesday. An older Swedish woman travelling in the car also died in the shooting, along with Sylvain Mollier, 45, a French cyclist who apparently stumbled across the attack in Chevaline.
The couple's four-year-old daughter Zeena lay undiscovered under her mother's corpse for eight hours after the murders, while her seven-year-old sister Zainab remains in a medically induced coma after being shot and beaten.
Two relatives of the orphans, who were not identified for "security reasons", have travelled to France alongside a British social worker. They are expected to visit the girls in the coming days, although it is unclear when they will be able to see Zainab as she continues to be treated in hospital. Both youngsters are under police supervision.
Surrey Police also revealed they had sent family liaison officers out to the country. Investigators from the force entered the al-Hillis' family home in Claygate, Surrey, after a team of four French officers, led by Colonel Marc de Tarle, arrived in the UK.
A tent was erected at the front of the address before scenes of crimes officers in full protective suits began combing through the family's belongings. The caravan in which the family had been staying at the Le Solitaire du Lac campsite in Saint-Jorioz was also examined by police.
Police plan to look at aspects of Mr al-Hilli's life to try to find a motive for the murders and also speak with his brother, named in reports as Zaid Hilli. Investigators have disclosed that Mr al-Hilli's sibling approached UK police to deny any feud with his sibling over money.
Public prosecutor Eric Maillaud said the brother would be interviewed along with the rest of the al-Hilli family as witnesses as part of the investigation.
It is also believed detectives will look into Mr al-Hilli's profession, with reports emerging that he was working as a contractor for a satellites technology company in Surrey.