TALLOIRES (AFP) - A man arrested on Tuesday in connection with the 2012 murders of a British-Iraqi family and a cyclist in the French Alps is a former policeman, said a source close to the case.

Another source said the 48-year-old man was sacked from the police force in June last year. The man was described as a quiet type who liked guns.

"The man, if it is indeed the same person we think, was dismissed in June" from the force, Antoine de Menthon, the mayor of the town of Menthon-Saint-Bernard said.

It is the first time anyone has been arrested in France in connection with the case, which has baffled investigators despite major efforts on both sides of the English Channel.

Saad al-Hilli, a 50-year-old Iraqi-born British tourist in France, was gunned down in September 2012 along with his 47-year-old wife Iqbal and her 74-year-old mother in a woodland car park close to the village of Chevaline in the hills above Lake Annecy.

Each was shot multiple times in their British-registered BMW estate car and more than two dozen spent bullet casings were found near the vehicle.

Mr and Mrs al-Hilli's two young daughters, then aged seven and four, survived the attack.