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.
The man arrested in France has a motorcycle helmet similar to one in an e-fit issued by police, according to a French broadcaster. BFM claimed the man lived alone in the mountains and was found with arms in his home.
In November, police released an image of a male motorcyclist they wanted to speak to in connection with the killings. at the time the helmet was said to be "very particular" and one of only a few thousand models worldwide.
Police are currently searching the house of the man arrested as part of the investigation into the deaths of four people in 2012, in village near Chevaline.
The French prosecutor has said the man is not a suspect at this time but is being questioned because he resembles an e-fit and was in the area at the time of the killings. He could be released as early as this evening.
Sources close to the probe have told ITV News that the arrest is a result of the photofit released in November. The arrest is the first of a number of the arrests and is believed to be critical to the investigation, the sources said.
In November, police released an image of a male motorcyclist they wanted to speak to in connection with the killings.
The French Gendarmerie released an artist's impression of a motorcyclist who was seen riding in the area shortly before the four murders took place.
The man's helmet was said by Mr Maillaud at the time to be "very particular" and one of only a few thousand models worldwide, with a bottom section which opened laterally to reveal the lower face.
Read more: Man arrested over Alps killings
Police in the UK have confirmed the arrest of a man in France in connection with the murder of four people in the Alps.
British engineer Saad al- Hilli, his wife Iqbal, her mother Suhaila al-Allaf and French cyclist Sylvain Mollier were all killed in the attack on September 5 2012.
In a statement Surrey police said:
"Surrey Police can confirm that an arrest has been made in France today in connection with the murders of four people near Annecy, southern France in September 2012.
"The arrest has resulted from a line of enquiry in France and is not as a result of the investigation carried out in the UK."
A 48-year-old man has reportedly been arrested by French police in connection with the investigation into the murder of four people in 2012.
On 5th September 2012, Saad al- Hilli, a British engineer, his wife Iqbal, her mother Suhaila al-Allaf and French cyclist Sylvain Mollier were all killed in the attack on September 5 2012.
Police investigating the murder of a British satellite engineer gunned down in the French Alps along with his wife and mother-in-law have released an image of a male motorcyclist they want to speak to.
The French Gendarmerie have released an artist's impression of a motorcyclist they are trying to trace who was seen riding in the area between 3.15pm and 3.40pm on the day the murders took place.
They are appealing for who anyone who might recognise the man in the image to come forward.
50 year old Saad al-Hilli from Claygate in Surrey, his dentist wife Ikbal and her elderly mother Suhaila al-Allaf were murdered on a remote forest road near Lake Annecy in southern France on September 5, last year. French cyclist Sylvain Mollier was also killed.
Iraqi-born Mr al-Hilli's eldest daughter Zainab was shot, beaten and left for dead, but survived. Her four-year-old sister Zeena lay hidden under her mother's corpse and was only discovered eight hours after the murders.
– David Hudson, the headmaster of Charlie Saunders' school, the Royal Latin in Buckingham
(Charlie was) a talented and very motivated boy who made a huge impact on the lives of every one who knew him.
He was a popular boy and threw himself into school life with 100% effort.
Charlie loved a wide range of sports and especially the great outdoors.
He will be hugely missed and we send our thoughts and prayers to his family, especially his mother and sister, at this tragic time.
Zainab Al-Hilli's state of health is understood to have improved in recent days, allowing her to travel back to the UK.
– A police source in Annecy
Zainab left France this morning at around 8am. Police from Britain accompanied the little girl.
Her departure follows that of her younger sister, Zeena, who returned to the UK last week after escaping the brutal attack unscathed. The four-year-old survived by cowering under her mother's skirts but she was only discovered eight hours after the killings.