ANNECY, France — French prosecutors focused Friday on a feud between brothers as they searched for a motive in the slayings of a British-Iraqi family vacationing in the French Alps.

Two young sisters survived the deaths of their parents and an older woman in the family car late Wednesday, as well as a French cyclist whose body was found nearby. The children, apparently the only witnesses to the shootings on an isolated Alpine road, were under police protection Friday.

Prosecutor Eric Maillaud said British police have reported that the girls' father was feuding with his brother over money.