LONDON : British police said Monday they had arrested a 54-year-old man in connection with the murders of three members of an Iraqi-British family and a French cyclist in the French Alps last year.

The man was detained on suspicion of conspiracy to commit murder in a "pre-planned arrest" in Surrey, outside London, where the al-Hilli family lived, a police statement said.

A French source close to the investigation told AFP that the man arrested was Zaid al-Hilli, the brother of Saad al-Hilli, who was shot dead, but British police did not immediately identify him.

Saad al-Hilli's wife Iqbal and her mother Suhaila al-Allaf were also killed in the family's BMW estate car at a beauty spot near Lake Annecy on September 5 last year.

The couple's two young daughters survived the shooting, one of them by huddling next to her dead mother's body for hours until police found her.

A French cyclist, Sylvain Mollier, was also shot dead, but investigators believe he was not a target and was just in the wrong place at the wrong time.

Zaid al-Hilli has already been questioned by police over the investigation.