Investigators into the murders of a British family in the French Alps were pinning their hopes on a seven-year-old girl wounded in the attack, as they struggled to make headway in the case.
Prosecutor Eric Maillaud said police hoped the girl, who remains in a medically induced coma after being shot and badly beaten in the attack, would be able to finally shed some light on the mysterious murders.
"She is a key witness," he said. "We hope that she will be able to tell us what she went through, provide us with descriptions of the murderer or murderers."
Prosecutors are also investigating if a family feud over money could have been the motive for Wednesday's brutal slayings. The brother of the British man slain in the attack has denied any such dispute to British police.
French police have so far failed to make much progress in the investigation into the killings.
Saad al-Hilli, a 50-year-old Briton born in Iraq, his wife Ikbal and his 74-year-old mother-in-law were gunned down in a forest car park in an Alpine tourist area on Wednesday.
Their seven-year-old daughter Zainab was left for dead. Their four-year-old daughter Zeena also survived the attack, having hidden undetected for eight hours under her dead mother's skirts.
A local man, 45-year-old Sylvain Mollier, was also killed after apparently stumbling on the attack on the family's car.
Maillaud said British police had told French authorities of a financial dispute between Hilli and his brother, but he cautioned against jumping to conclusions.
"The brother spontaneously presented himself to the British authorities, at first because he was worried and wanted to know if it was true that his brother had died in France," Maillaud said.
"He went back again today and told them: I have no conflict with my brother."
In France, Maillaud also revealed that Hilli was "totally unknown" to British and French intelligence services, contradicting media reports suggesting he had been placed under surveillance around the time of the last Iraq war.
It was unclear when the elder daughter might be in a condition to be questioned, he said.
"She is still under medical protection. The doctors have absolutely not given a green light for her to be interviewed," the prosecutor said. "If and when they do, it will happen in the presence of British diplomats."
He added however that she was doing better after surgery and was "out of danger".
Maillaud said a former Royal Air Force pilot who found the victims within minutes of their deaths had seen a "green or other dark-coloured four-wheel drive car."
Four-year-old Zeena had been unable to help investigators, he said. Officers had to be "extremely careful about the declarations of a traumatised little girl", he added.
She was being cared for by child psychology experts and British embassy staff and was due to be returned to England soon, he said.
Post-mortems on the victims' bodies had begun and results were due late Friday or early Saturday. The response to a formal request for DNA samples from Britain was also expected to arrive on Saturday.
The family were killed in their British-registered BMW estate car in a forest car park near the village of Chevaline in the picturesque Haute-Savoie region.
Each had been shot multiple times, including at least once in the head.
Maillaud said about 25 spent bullet casings were found near the vehicle.
"The number of casings suggests that there were two shooters," a police source said. "This changes things a bit, because the scenario from the beginning was a single shooter."
The family, from Surrey in southern England, had been staying since Monday at the nearby Saint Jorioz camp site.
French authorities on Friday formally opened two criminal investigations into the shooting: one for the pre-meditated murders of the four victims and the other for the attempted murders of the two child survivors.
Three French police officers have arrived in England to work with British police on the case and a fourth is due to arrive on Saturday, officials in London said.
Authorities unblocked access to the site of the killing in Chevaline Friday but few signs remained of the incident aside from some broken glass, tyre tracks and small traces of blood.
In Britain, bouquets of flowers were building up outside the family's spacious home in Claygate, a teddy bear placed among them.
"They were a lovely, lovely family," said one of a group of tearful mothers whose children attended the local primary school with the two girls.