Eleven-year-old Solaine Thornton was shot dead while playing on a swing in her garden on Saturday.
The suspect held over the fatal shooting of an 11-year-old British girl in France is under investigation for murder, prosecutors say.
Solaine Thornton was shot dead while playing on a swing in her garden on Saturday evening.
Prosecutors said the suspect, a 71-year-old neighbour, got to within 10m of the girl’s father before opening fire through a hedge.
He had been in conflict with the family over building work on their property.
The suspect then shut himself in his house in the village of Saint-Herbot, north of Quimper in Brittany, following the incident but gave himself up to police an hour later.
His wife, who was also arrested, surrendered half an hour after he did, but she has since been released.
Prosecutor Camille Miansoni said the couple had been in conflict for years with their British neighbours over works taking place on their property.
The suspect was “profoundly exasperated” over the works, which he said affected his privacy and caused disturbance to him and his wife.
Mr Miansoni said the suspect had gone into his home to fetch one of the guns and returned to the garden before opening fire and shooting three or four times through a hedge. This suggested a level of premeditation, he said.
“It appears that he clearly aimed at the father, that he aimed at his wife, but however he seems less clear as to a possible admission that he aimed at the girl,” Mr Miansoni said.
The girl and her eight-year-old sister had been playing on a swing as their parents tended the barbecue when the neighbour began firing.
The younger girl ran to another neighbour’s house to raise the alarm and is now said to be in shock.
A local resident told French media that the younger child ran to neighbours shouting: “My sister is dead, my sister is dead”.
The victim’s parents Adrian and Rachel Thornton were also hurt and are in hospital.
A search of the couple’s property also uncovered two rifles, one of which had not been previously declared,
The couple, both Dutch nationals, tested positive for alcohol and cannabis. They had no previous convictions, prosecutors said.
Mr Miansoni said the suspect had expressed regret, and that a mental health assessment had found nothing notable.
The UK Foreign, Commonwealth and Development Office (FCDO) said it was providing assistance to a British family.