The suspect in the fatal stabbing of a French police officer had been seeing a psychiatrist prior to the attack, French authorities have said.
Police detained a fifth person on Sunday after a police officer was stabbed in the Paris suburb of Rambouillet on Friday, April 23.
The suspect, a 36-year-old Tunisian national so far named only as Djamel G, was killed in the aftermath of the attack. French prosecutor François Ricard told the media on Sunday that three of those arrested were members of the suspect's family. A couple he previously lived with have also been taken into custody.
Ricard said on Sunday that the suspect was thought to have staked out the station before the crime took place.
Police found a Koran and a prayer rug in the seat compartment of his scooter after he stabbed the victim: a mother-of-two in her 40s, who had left the police station to change her parking disc.
Ricard added that France was working with the Tunisian authorities on the case. The suspect is understood to have travelled to the north African country earlier in the year.
French President Emmanuel Macron has branded the killing an act of Islamist terrorism. Ricard said at the press briefing that the murder was "the 17th Islamist terrorist act committed in France since 2014 again security forces."
The National Anti-Terrorist Prosecutor's Office (PNAT) has launched an investigation into the charges of "murder of a public official in relation to a terrorist undertaking and terrorist conspiracy."
On Saturday, Ricard told reporters at the scene that according to witnesses, the killer had shouted "Allahu Akbar" during the attack.
In his update on Sunday, the prosecutor added: "The presence of certain disorders of the personality could also be observed. In this respect, his father stressed that his son had adopted a rigorous practice of Islam. On the other hand, he also mentioned various behavioural disorders that he'd noticed in his son earlier in the year."
The suspect went to psychiatric consultations in Rambouillet on February 19 and February 23 this year, but was not assessed as needing hospitalisation or treatment, according to Ricard.
He then travelled to Tunisia from February 25 to March 13. Tunisia's Foreign Affairs Ministry offered its condolences to the victim's family, the French government and people and said Tunisia expresses its, “total condemnation of extremism and terrorism.”
The 49-year-old victim had two daughters, aged 18 and 13, and was named Stephanie by Macron, who wrote: "The Nation stands with her family, her colleagues and security forces. In the fight against Islamist terrorism, we will not give up."
Prime Minister Jean Castex said on Twitter: "The Republic has just lost one of its everyday heroines, in a barbaric and infinitely cowardly act. I want to express the support of the entire nation to her family. To our security forces, I want to say that I share their emotion and indignation."
Interior Minister Gérald Darmanin has called on prefects to strengthen security measures around police stations and gendarmerie brigades.
The SCPN union, which represents police chiefs, said on Twitter that the service was "once again bereaved by a despicable attack. We support the family and friends of our colleague."
It added: "All police officers of all ranks and all corps know that to serve is to risk one's life in the face of fanaticism and extremists."