"Checks will be carried out” to see if Nordahl Lelandais was involved in the grim murders of Saad al-Hilli, his wife and mother-in-law and a French cyclist, the prosecutor in the town of Annecy, Véronique Dénizot, told The Local.
The al-Hillis were gunned down in broad daylight on a mountain road near Annecy in what appeared to be an execution-style attack by a killer or killers who probably had military or other training in the handling of firearms, police said at the time.
Investigators said the attack - which the Iraq-born couple's two young daughters survived, with one of them hiding for hours under her dead mother's skirt - was carried out in a cold, professional manner.
Police never found any motive for the crime despite lengthy investigations in Britain, France and Iraq.
Prosecutor Dénizot said that "within a reasonable time frame" her team of investigators would examine whether there are any links to Nordahl Lelandais, who is custody over the disappearance of a nine-year-old girl in August and the murder of a soldier in April.
Lelandais, who had been a soldier in the French army where he worked as a military dog trainer, was charged this week with the murder of Arthur Noyer, a 24-year-old soldier last seen on April 12th hitchhiking in the town of Chambery after leaving a nightclub.
Lelandais, 34, was previously charged for the abduction and murder in August of an eight-year-old girl named Maelys de Araujo who disappeared from a wedding only a half-hour drive from Chambery.
Chambery is about 50 km from Annecy.
French media were quick to ask whether police had captured a serial killer who may have been responsible for a a string for disappearances or murders in the Alps in recent years.
Chambery Prosecutor Thierry Dran confirmed that a number of cold cases would be reopened.
"We are going to look at all the disturbing disappearances which have taken place in this region," he told reporters, without detailing which cases would be re-examined.
The Annecy prosecutor said that currently there was no evidence to suggest that Lelandais might be linked to the al-Hilli murders but that investigators would in due course probe his whereabouts on September 2012, the day the family were gunned down.
Lelandais, who was unemployed and lived with his mother, has denied all charges against him.
Investigators found that he had looked up "decomposition of a human body" soon after the soldier's disappearance.