French and British investigators probing a quadruple murder in the French Alps said Friday they were looking at a dispute over a family inheritance and possible industrial espionage as possible motives for the unexplained slaying.
"We have made great advances" in the investigation, said Eric Maillaud, the prosecutor of Annecy who is in charge of an investigation conducted jointly with British police.
Three members of the British-Iraqi al-Hilli family were shot dead in their BMW station wagon on September 5, 2012 in a woodland car park close to the village of Chevaline in the hills above Lake Annecy.
A French cyclist Sylvain Mollier was also found shot dead.
The two al-Hilli daughters, then aged four and seven, survived the attack in which more than 20 bullets were fired.
At a press conference here to mark Thursday's first anniversary of the killings, both French and British investigators evoked the possibility that a family feud over a multi-million-dollar inheritance lay behind the tragedy.
Maillaud told a press conference that the victim, Saad al-Hilli, and his brother Zaid, were locked in a bitter dispute over properties in Iraq and elsewhere.
"This is being followed up actively," he said, adding that the two brothers "initially worked together to regain their father's property" in Iraq but soon fell out.
He said the theories ranged from the possibility that Saad al-Hilli was "trying to get himself declared as the sole inheritor" of his father's fortune to his brother Zaid al-Hilli "stealing money from his father for a long time."
Maillaud said it was also possible that relatives of the two brothers in Iraq were embroiled in a dispute over a house and land in a plush Baghdad neighbourhood that had been owned by the father, Khadem al-Hilli.
"The question arises if those in Iraq who are in control of the father's property do not have an interest in making the two brothers disappear because they want to get it back," he said.
In June Maillaud said investigators were trying to track the destination of calls made to Romania from Zaid al-Hilli's home phone in the weeks prior to the attack.
Shortly after that announcement, Zaid al-Hilli was arrested by British police and questioned on the basis of suspicion of conspiracy to murder. He was subsequently released without charge but remains under bail pending further enquiries.
British detective superintendent Nick May said: "Zaid al-Hilli is a nominated suspect. He has been arrested and we continue to make enquiries."
May said Zaid al-Hilli will answer police bail next month.
"There is a tremendous amount of work that needs to be done...several audios to be digested," May said. "There are other lines of enquiry."
Maillaud also evoked the possibility that an explanation for the murder could lie in Saad al-Hilli's career as "a brilliant engineer" working with a British firm specialising in satellites which worked with numerous foreign countries.
"If you are talking about foreign states and industrial espionage, you could also be talking about secret service involvement," Maillaud said.
"It is an extremely complex aspect of the investigation, which will take a lot of time and perhaps will not lead anywhere. But this avenue of investigation is far from being concluded."
Maillaud reiterated that the investigators did not think French cyclist Mollier was in any way involved, repeating his belief that he had simply been "in the wrong place at the wrong time."