French Interior Minister Gérald Darmanin told France 2 in an interview Friday that authorities were working to verify more details about the suspect’s background after the attack that left two people seriously injured.
The minister also confirmed that the incident was treated as “an act of Islamist terrorism”.
The main suspect was not known to police for “radicalization” but was arrested last month for bringing a screwdriver, Darmanin added.
Police say seven people were arrested in the attack. Five of the arrests were made in an apartment “likely to be used by the main suspect,” a judicial source told CNN on Friday.
Although the victims were not named, they are both employees of the French documentary production company Premières Lignes, according to company founder Paul Moreira.
Moreira said the two were attacked with a “kind of cleaver”
In a statement on Facebook, Charlie Hebdo magazine expressed “support and solidarity” to Premières Lignes and “to those affected by this heinous attack”.
Annie Hidalgo, Mayor of Paris, tweeted that “it is once again freedom of expression that is being targeted”, while former Prime Minister Manuel Valls said on Twitter that it gave him the feeling of “reliving a nightmare” .
The knife attack took place during a trial of 14 suspects for their alleged involvement in a series of three-day terrorist attacks in January 2015, which began in the offices of Charlie Hebdo and ended in a kosher supermarket.
A total of 17 people were killed in the 2015 attacks, carried out by brothers Said and Chérif Kouachi and their accomplice Amedy Coulibaly. The suspects currently on trial are accused of providing these men with logistical support.
After the knife attack on Friday, Luc Hermann, director of Premières Lignes, criticized what he said was a “total lack of protection of this building after the attacks on Charlie Hebdo”.
CNN’s Gaëlle Fournier and Niamh Kennedy contributed to this report.