PARIS (Reuters) - French police raided several houses on Tuesday in an operation targeting suspected associates of the man who killed a police commander and his partner last week in an attack claimed by Islamic State, judicial officials said.
One source inside the judiciary said investigators were digging into the network of individuals with past ties to Larossi Abballa, who pledged allegiance to the militant group and told negotiators during the attack that he had answered a call to "kill infidels at home with their families."
"There was a chance that these people might carry out other attacks against police officers. We were removing any doubt," the Versailles prosecutor leading the investigation said.
Three individuals were targeted in the morning swoop. One man was arrested but later released.
Abballa stabbed 42-year-old Jean-Baptiste Salvaing to death and used a knife to kill the police commander's partner before he was shot dead by elite commandos.
Tuesday's raids came after the Paris prosecutor's office placed two of his suspected associates under investigation over the weekend for having links to a terrorist group.
The men, identified as Charaf-Din Aberouz and Saad Rajraji, were convicted by a French court in 2013 of involvement in a militant recruitment network alongside Abballa. All three spent time in jail.
Aberouz and Rajraji first made contact with each other more than six years ago on Facebook, where they discussed the legitimacy of armed jihad and suicide attacks, as well as events in Afghanistan, according to court documents seen by Reuters.
By 2010, Aberouz was leader of a local group of militant sympathizers. On one occasion he trained group members how to slit the throats of rabbits in a wood outside Paris and jokingly described himself to Rajraji as a "future mujahideen with a thirst for blood", the documents showed.
Aberouz left France for Pakistan in January, 2011. He was expelled by the Pakistani authorities months later and arrested by French police in May the same year. During Aberouz's time away, Rajraji headed the local group, the court documents showed.
The judiciary source said investigators who raided Rajraji's house had found on a scrap of paper the email address of Fabien Clain, the man who recorded Islamic State's claim of responsibility for the attacks on Paris in November that killed 130 people.
At this stage, investigators have not made any direct link between Aberouz and Rajraji and the killings last Monday.
(Reporting by Chine Labbé; Writing by Richard Lough; Editing by Andrew Callus and Hugh Lawson)