Image caption Zaid al-Hilli previously denied any feud with his brother Saad

A 54-year-old man has been arrested in Surrey in connection with the murder of his brother and three other people in the French Alps.

Saad al-Hilli and his wife Iqbal, from Claygate, Surrey, her mother Suhaila al-Allaf and French cyclist Sylvain Mollier were shot on 5 September.

The family were on holiday by Lake Annecy when they were attacked.

Zaid al-Hilli, Saad's brother, was arrested at an address in Chessington.

He had previously denied there was any feud between him and his brother.

'Unanswered questions'

Two judges in Annecy are investigating phone calls made to and from the home of Zaid al-Hilli in the three-week period before the family left for a holiday, the BBC's Christian Fraser, in Paris, reports.

He said: "The French investigators have expressed frustrations since last year that they have not been able to interview Zaid as a suspect.

Lake Annecy shootings The shootings took place in a forest car park

Saad al-Hilli was an Iraqi-born British citizen. His wife held an Iraqi passport and her mother was a Swedish national

Cyclist Sylvain Mollier was a 45-year-old father of three who worked in the area

Several witnesses saw a car speeding away from the scene

Police were instructed not to disturb the bodies - which was why the al-Hillis' daughter Zeena was not found for eight hours

"They did visit him in March but he was interviewed on that occasions only as a witness. Today's pre-arranged arrest is presumably an opportunity to put some of the unanswered questions, under caution.

"French gendarmes have travelled to Britain but will not be involved in the interview. We understand the questions will be put by the Surrey police; though you can assume the French are directing proceedings."

Annecy prosecutor Eric Maillaud told news agency AFP: "We felt there were enough reasons to take him into custody.

"We need to ask him questions about his schedule, his relationship with his brother and the family inheritance."

About 100 British and French police officers are investigating the deaths.

The family's home in Claygate was searched by French investigators after the shootings.

Analysis There have been difficulties in the past 10 months negotiating two very different legal systems. Under the French criminal justice system investigating magistrates have independent powers to search premises or demand access to bank accounts and phone records. In Britain search warrants have to be approved by the courts. Last year a Joint Investigation Team (JIT), was set up under the auspices of the EU's judicial co-operation policy, Eurojust, to overcome these kinds of problems. The setting up of a JIT suggests a strong belief that the case will be solved in Britain.

Last month, Surrey Police issued an appeal to help trace a vehicle, thought to be a UK-registered right-hand-drive 4x4, which was seen near the crime scene.

The car was being driven on the Combre d'Ire Road in Chevaline, near Annecy, about 20 minutes before the shooting, the force said.

Surrey Police also said at the time that the Surrey and Sussex Major Crime Team had been working closely with the French authorities on "a number of lines of inquiry" in the UK.

Mr and Mrs al-Hilli's daughters survived the shooting.

Four-year-old Zeena was discovered under her mother's body inside the family car, eight hours after the shooting.

Her seven-year-old sister Zainab was found with serious head injuries after being shot and beaten.