Shots to the head killed three of the four found dead in the Alps in what the prosecutor has called an act of "extreme savagery." A four-year-old survived by appearing "completely invisible."
Three bodies - one man and two women - were found inside a British-registered BMW. Two young girls, the daughters of two of the victims, survived the attack.
The fourth body was that of a cyclist who seemed to have arrived at the scene by chance.
"It was clearly an act of extreme savagery and it was obvious that whoever did this wanted to kill," said Prosecutor Eric Maillaud.
Police have confirmed that the car belonged to the driver, a 50-year-old Iraq-born resident of Surrey, England.
The elder of the two women murdered was identified as the dirver's 74-year-old mother in law, a Swedish passport holder. The younger woman was identified as the driver's wife, and mother of the two girls who survived the attack.
'No state to be interviewed'
Maillaud said the older of two young sisters who survived had been placed in an induced coma ahead of further surgery in Grenoble. The prosecutor said the girl, about 8, had been shot in the shoulder and suffered multiple "extremely violent" blows to the head.
"Her life is not in danger but obviously she is no state to be interviewed," Maillaud said.
Maillaud also explained how the 4-year-old spent eight hours crouching beneath her mother's corpse, even after the first firefighters and police officers to arrive failed to spot her. The officers had orders not to interfere with the car pending the arrival of forensics experts, who did not get there until midnight.
The family had stayed since September 3 at the Saint Jorioz campsite, where they were reported missing on Wednesday.
On Friday AFP quoted the prosecutor as saying that a family feud may have been the reason for the crime.
mkg, rg / rc (AFP, Reuters, AP)