Volkswacht Bodensee - Four die as family plunges from balcony in Switzerland

The circumstances around the family drama in an upmarket neighbourhood of the picturesque town on the shores of Lake Geneva remained unclear.

But police said the five members of the same family -- a man, 40, his wife, 41, and her twin sister, along with the couple's daughter, eight, and son, 15 -- had gone off the balcony after two officers showed up at their door early Thursday.

All of them except the son died when they hit the ground, while the boy was taken to hospital in serious condition, police said.

"The officers were unable to enter the apartment, and it appears that at that moment, the decision was made by this family to throw themselves off the balcony," Jean Christophe Sauterel, spokesman for the Vaud cantonal police, told public broadcaster RTS.

An investigation has been opened, but police have already concluded that the incident happened "behind closed doors", and that no one else was in the apartment at the time, he said.

- 'Like a bad movie' -

The officers at the apartment door had been there to execute a warrant for the father in connection with the home-schooling of one of the children, a police statement said.

They knocked on the door and heard a voice ask who they were, but once they answered, the apartment went quiet, it said.

After failing to make contact, the officers left, but "in the meantime, a witness called the police to say that people had fallen from an apartment balcony," the statement said.

The bodies were found at the foot of the building, near Montreux's famous Casino at around 7:00 am (0600 GMT).

"I saw five bodies around 10 metres from the building, three on one side and two on the other," one neighbour told the Tribune de Geneve daily.

"It was difficult to understand what I was seeing. It was like a bad movie."

Sauterel said the witness who called had seen the family members hit the ground, and was receiving professional support.

A number of other people connected with the drama, as well as first responders had also been offered counselling, he said.

Sauterel told AFP that the family were all French citizens who had been living in Switzerland for some time and had resident status.

Police did not provide further information about the family, but the Tribune de Geneve reported that neighbours described them as "discreet".

The father appeared to have been working from home, the paper said, citing neighbours.

The mother was a dentist who had worked in Paris, while her twin sister was an ophthalmologist.

R.Adler--BTB