"I don't want to go into details on when or what NPSS has known about that person. What we can say is that we did know of that person," Sjovold told a press conference when asked what the police had known about the attacker and when.
The police are still looking into the motives of the suspect and whether his behavior might prompt others to do the same, the NPSS chief said.
"Of course, we are also working on finding out whether this can inspire others to undertake terror. That's something we have a big focus on now. But as of now, we cannot say that we are seeing such a thing," Sjovold said.
Earlier in the day, Norwegian media reported that the attacker's family had a restraining order against him and the police spoke to the suspect in 2020. The man, who media say is in his 30s, was arrested on Wednesday evening after shooting several people with bow and arrow. Apart from the five people killed, three are wounded.
The police said they consider the attack as terrorist act, but will not change the general threat assessment of the country from the current moderate level.