A baby died when a family of 12 leapt from their second floor balcony in Paris claiming they were fleeing the devil.
Eight more were injured, some seriously, in the tragedy when they jumped 20ft into a car park in Paris suburb of La Verriere.
The baffling incident occurred when a wife woke to see her husband moving about naked in the room, police said.
She began screaming 'it's the devil! it's the devil!', and the man ran into the other room where 11 others adults and children were watching television. One woman grabbed a knife and stabbed the man before others pushed him out through the front door.
When the man forced his way back in, they all began screamed in terror and leapt from the balcony screaming 'Jesus! Jesus!'
The naked man also leapt from the balcony, detectives said.
A four-month old baby died in his mother's arms, while a two-year-old was critically injured in yesterday’s incident.
Police said they had found no evidence of hallucinogenic drugs or unusual religious rituals.
Versailles assistant prosecutor Odile Faivre added: “A wife in the next room saw her husband moving around naked and began screaming that he was the devil.
“In the confusion following this apparent case of mistaken identity, the naked man's sister-in-law stabbed him in the hand and he was ejected through the front door of the flat.
“When he attempted to get back in, panic erupted and the other occupants of the flat fled by jumping out of the window.
“A number of points surrounding this incident remain to be cleared up,” Mr Faivre said.