A man has been arrested in France in connection with the killings of a British engineer and his family.
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 5 September 2012.
Local cyclist Sylvain Mollier was also murdered.
Surrey Police said they 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 inquiry in France and is not as a result of the investigation carried out in the UK."
The man, believed to be a 48-year-old, was reportedly arrested in Chevaline.
Last month Mr al-Hilli's brother Zaid al-Hilli, who was arrested in connection with the shooting, had his bail cancelled by Surrey Police after the force deemed there was not enough evidence to charge him with a crime.
The 54-year-old, from Chessington, Surrey, said he was "relieved", but French investigators said they still had "many questions" to ask him.
Since the deaths, speculation has surrounded whether the shooting was linked to the al-Hillis' native Iraq, or Saad al-Hilli's work as a satellite engineer.
Annecy prosecutor Eric Maillaud previously said that police in France were still looking for a motorcyclist seen riding in the area between 3.15pm and 3.40pm shortly before the four murders took place, and a BMW 4x4 also seen there.
The murder scene was discovered by cyclist Brett Martin, who found Iraqi-born Mr al-Hilli, 50, his 47-year-old dentist wife and her elderly mother shot to death in their BMW.
The al-Hillis' first-born daughter Zainab was shot in the shoulder and beaten, but survived.
Her then four-year-old sister Zeena lay hidden under her mother's body and was only discovered eight hours after the murders.
The al-Hilli brothers were alleged to have been locked in an inheritance dispute centred on the £825,000 home in Claygate where Saad and his family lived after their mother died from a heart attack in 2003.
Zaid, who inherited half the property, claimed that in 2011 his brother began to demand his share of the house "there and then" and pinned him down during a row.
The two men never spoke again except through lawyers, but Zaid denied rumours that he had threatened to kill his brother.
He said he knew little about a Swiss bank account containing the proceeds from their father's business in Iraq and would not comment on claims that he attempted to access it using an expired card or tried to fake their father's will.
In November, police released an image of a male motorcyclist they wanted to speak to in connection with the killings.
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.
It was described as black or dark-coloured, with a lateral opening at chin level and French police said the only similar helmet on the market is made by GPA and is an ISR model.