The French man, a plumber, has been receiving treatment since 2017 for depression and psychotic behaviour, the prosecutor said.
He was already held in 2019 after stabbing his partner in the shoulder blade when she was pregnant with their third child and trying to kill himself. She had refused to press charges, the prosecutor said.
He was treated again after that attack, and said he did not mean to harm her. The case was dropped as he was deemed to be “mentally deficient”.
The couple, who had met in high school, married in October.
Police broke in through a bedroom window of their ground-floor flat to find a “very violent crime scene” covered in blood, the prosecutor said.
Online scam drives Thai man to kill his wife and children, police say
Online scam drives Thai man to kill his wife and children, police say
A police source said the mother was lying in the corridor, while the children were found dead in their rooms, in the kitchen and bathroom.
“The mother and the two girls had received a very high number of knife wounds,” the prosecutor said.
The two younger boys had no stab wounds and may have been suffocated.
Neighbours told police they had heard cries downstairs during the night of December 24 to 25.
The suspect, who was arrested near his father’s home in the neighbouring town of Sevran on Tuesday morning, had not yet been questioned but told police he “knew why he had been detained”, and “spoke of his unhappiness and depression”, Bladier said.
He had wounds to his hand.
An inquiry has been opened into the murder of minors under 15 years old, and murder by a partner. Autopsies were to be carried out in Paris on Wednesday.
People tied flowers to the railing outside the family’s flat on Christmas Day. The local community is in shock.
Iraqis protest after father kills YouTuber daughter
Iraqis protest after father kills YouTuber daughter
“His wife was kind, she spoke to everybody,” said one local called Antonio, 69, who did not give his surname.
The Paris region has recently seen a series of infanticides.
In late November, a 41-year-old man confessed to killing his three daughters, aged four to 11.
Police found them dead in his home in the town of Alfortville, in the southeastern suburbs of the capital.
A month earlier a gendarme killed his three daughters before killing himself at his home in Vemars, northeast of the capital.
On average, a woman is killed every three days in France. Some 118 women were killed by their partner or ex-partner in France last year.
Police registered 244,300 victims of domestic violence, mostly women, in 2022 – a 15-per cent increase – in what rights groups believe is a sign that law enforcement is taking the problem more seriously.