Arrests in mysterious case of French family who disappeared

The entrance and mailbox, sealed by police, of the house belonging to the missing Troadec family in Orvault, near Nantes, western France. Photo / AP

A development has occurred in the case of the French family who mysteriously disappeared.

The BBC, citing a local media report, says police have arrested two of their relatives. Police are investigating murder, abduction and illegal confinement.

The sister and brother-in-law of Pascal Troadec, one of the four missing family members, have been detained in Brest.

The others missing are Pascal's wife Brigitte, son Sebastien, 21, and daughter Charlotte, 18.

The BBC says several items belonging to the family, last seen on February 17, have been found.

It says that authorities believe there is a chance some of them are alive.

The family is from Nantes. Brest is about 300km away.

AFP reports that the relatives had previously been questioned by police.

Prosecutor Pierre Sennes said at the weekend that some of the missing could still be alive, Le Figaro reports.

Last week, police found Sebastien's car in Saint-Nazaire. The family's two other cars were at their house.

A social security card and a pair of trousers belonging to Charlotte had been found by a jogger in a forested area near Brest, the BBC reports.

Investigators had found bloodstains matching the DNA of the parents and Sebastien, but not of the daughter at their home.

Traces of blood were found on Sebastien's phone, on Brigitte's watch and under the stairs.

Authorities were told of the disappearance by Brigitte's sister.

AFP reported that investigators had focused on Sebastien, who had been sentenced to carry out community service after a conviction in 2013, of making death threats on his blog.