A father and son who died on a walking trip in the French Alps have been named by the Foreign Office as Peter and Charlie Saunders.
A British cyclist has described how he found the bodies of the Surrey family who were murdered in the French Alps.
A French judge and prosecutor are to travel to the UK, as part of their investigation into the murder of three Britons in the Alps.
No charges are being brought against a man arrested in connection with the killing of a Surrey engineer and his family, French prosecutors have said.
French prosecutor Eric Maillaud said he was released from police custody after investigators found "no direct link" between him and the events of September 5.
The searches and interviews of the last three days have not enabled us to establish a direct link between the events of 5 September 2012 and this man, a war weapons enthusiast, who looked very like the e-fit released on 4 November 2013 and who was near to the place where the incident took place when it happened.
The weapon used in the crime has not been found, neither has the helmet which featured in the e-fit, nor the motorbike described by several witnesses which investigators were looking for.
French police have released without charge a former policeman being questioned in connection with the Alpine murders of a British family and a French cyclist, according to the Guardian.
Police said that there was "no direct link" found between the 48-year-old man and the case.
However the Annecy prosecutor, Eric Maillaud, said the man, who police do not wish to identify, was still being investigated on unrelated arms trafficking charges after an arms cache of vintage weapons was discovered at his home.
This "illicit activity was committed as part of an organised gang", the statement said.
The man was arrested on Tuesday, in what had appeared to be a breakthrough in the 18-month old quadruple murder investigation.
When the police issued the above photo-fit image last year, they received around 100 phone calls from the public.
A number of those phone calls led them to the 48-year-old man they now have in custody - someone who has spent 20 years as a police officer, acting more as a traffic officer than a criminal officer.
He left the police force in 2013 and has since gone on to work in the security industry in Switzerland.
A large number of guns and grenades have been seized from properties linked to the man since his arrest.
In a press conference today, French police investigating the Alps murders expressed their anger that the above image of a 48-year-old man currently in custody had been leaked to the media.
He was a hunter who lived close to the scene of the crime and was known to have an interest in collecting WWII guns, the prosecutor said.
He was not abroad at the time of the killings and it would have been logistically possible, given his movements, to have been in the area when the murders were committed.
A Luger weapon found at his house was not the same as the one used to kill the al-Hilli family, the prosecutor said.
A second man is in custody in connection with the Alps murders, a French prosecutor said today.
"We discovered a great number of munitions, explosives and detonators at his house," he added, saying the man may be involved in arms trafficking and was likely the business partner of a 48-year-old man arrested earlier.
He could not confirm a direct link between the arrest and the al-Hilli deaths.
The prosecutor in the Alps murder investigation has told a news conference that the case is not yet resolved.
Zaid al-Hilli told ITV News that his family was "very encouraged" by the arrest made in the investigation into the death of his brother and his family.
"We are very encouraged by the recent developments. Hopefully we will get to the truth," he said.
But he added: "I don't want to raise my hopes."
The brother of Alps murder victim Saad al-Hilli said the arrest of a 48-year-old - believed to be a former policeman - in connection with the killing, is "better than nothing".
Last month Zaid al-Hilli, who was arrested in connection with the shooting, had his bail cancelled by Surrey Police after the force decided there was not enough evidence to charge him with a crime.
Asked on Sky News whether this arrest, if it leads to a prosecution, would bring closure to him, he replied: "Well of course, I mean, anything is better than nothing. We'll see what happens. We can't raise our hopes."
There is a gathering sense here tonight that this investigation is finally gaining momentum. This was a crime, which of course shocked, but quite swiftly seemed to baffle police, as they searched for a motive and then it seemed to frustrate them, as they searched for evidence.
As much as French investigators are trying to play down events here, they say the man being questioned here is being questioned as a witness, not as a suspect but it is really hard to disguise the idea that a breakthrough might be imminent.
The man we know was a former policeman. It has been reported by French media that weapons were found at his home. French police have four days to question him before charging but tomorrow the prosecutor is talking about holding a press conference. That suggests there is something significant to say.
A 48-year-old man arrested in connection with the the killings of a British engineer and his family in France is believed to be a former policeman.
Saad al-Hilli and his wife Ikbal, from Claygate in Surrey, and her mother Suhaila al-Allaf, who lived in Sweden, were all fatally shot on a remote forest road in Chevaline near Annecy on September 5 2012. Local cyclist Sylvain Mollier was also murdered.
French police today arrested a 48-year-old man, from the Haute-Savoie region of France, in connection with the killings.
According to local media, the man is a former municipal policeman who lived close to the scene of the murders in Chevaline. Investigators were said to be looking into places that he had frequented.