LONDON (Reuters) - French police investigating a quadruple murder on a remote Alpine road two months ago have widened their probe to gun users and mentally disturbed people in the region after failing to find a motive for the killing, the BBC reported on Saturday.
Officers plan to investigate hundreds of people fitting the profile over the unexplained shooting of three members of a British family and a French cyclist near the village of Chevaline, close to the Swiss and Italian borders.
Investigators were looking for someone "who puts no value on human life, so someone who has doubtless killed before," French prosecutor Eric Maillaud told the BBC, but cast doubt on the theory that the murderer was a professional assassin.
Saad al-Hilli, an Iraqi-born British engineer, was found shot dead with his wife and mother-in-law in their BMW car on a remote mountain road near the village of Chevaline, with the body of a cyclist, Sylvain Mollier, discovered nearby.
They were killed in what appeared to be execution-style murders, with at least two hits to the head from a semi-automatic pistol.
"We are looking at all mentally unbalanced people, very violent or known to be capable of violence, using weapons," Maillaud said, in comments translated by an interpreter.
"And also, without wanting to link the two, everyone connected with the world of guns, hunters, collectors and members of shooting clubs, some of whom could have psychiatric problems," he added.
People over the border in Switzerland and Italy as well as in France would be investigated, he said.
Hilli's two daughters survived the attack, despite the gunman trying to kill the eldest, 7-year-old Zainab, by beating her around the head after running out of bullets.
Four-year-old Zeena was found safe hiding beneath the legs and skirt of her dead mother in the backseat of the car.
The brutality and unexplained nature of the killings led to prominent coverage of the case in British media.
Investigators have said previously they were looking at various theories, including robbery, a family feud, a possible link to Hilli's work in the aerospace industry or his Iraqi origins.
Maillaud said investigators remained undecided whether the Hillis were murdered as part of a contract killing, but were "99 percent sure" that the cyclist was not the shooter's target.
"We are further than day one, but still no motive," he said.
"The one thing, however, that the investigators say is that if it was a contract it was carried out very badly. We have the impression that it was carried out extremely quickly and not in a very professional manner."
(Reporting by Tim Castle; Editing by Stephen Powell)