As of 10pm, investigators had few leads in the two stabbing deaths, which occurred just after 4pm on the premises of the Wilds Minne School, a school for first through seventh graders.
Police haven't established the number of involved perpetrators nor their connection to the victims.
According to police, the female victim worked at a daycare facility near the school.
“We know that it was one of the women who worked in a private daycare in the area. The municipality is now assisting in terms of how the centre will cope with the situation,” Mayor Harald Furre told broadcaster NRK.
Fædrelandsvennen reported that the woman was an ethnic Norwegian in her 40s.
Terje Kaddeberg Skaar of the Agder Police said there is little or no evidence to suggest that there were eyewitnesses to the stabbings.
“We have therefore not established if there is a relationship between the two victims,” Skaar said at a Monday evening press conference.
Police were notified of the stabbings at 4.10pm. The first reports were that a woman and a child were stabbed, and that both were taken to the Hospital of Southern Norway with serious injuries.
The woman was declared dead at 5.46pm and the boy died about 15 minutes later, police said.
Wilds Minne School official Anne Marie Mauland Mansoor told Fædrelandsvennen that no students were directly involved in the incident. According to her, no students saw what happened.