The daycare centre, located in Høje-Taastrup near Copenhagen, is involved in a case in which a 14-year-old work experience student admitted sexually assaulting five children.
West Copenhagen police are therefore looking for witnesses who may have seen anything suspicious in the area around the Taastruphøj daycare centre, located on the Taastrupgårdsvej road, just before midnight on Tuesday.
Fire services were continuing work to put out the fire well into Wednesday, when forensic examination of the scene was scheduled to begin.
The daycare centre was reported to police by Høje Taastrup Municipality last week in connection with the assault case involving the 14-year-old.
On Tuesday, TV2 reported that that the boy had admitted last week to committing the assaults, which involved touching and kissing the young girls.
"We are prioritising investigation of both the fire and the report from the municipality very highly, and we are naturally sensitive to the possible connection between the cases," Deputy Chief Superintendent Peter Malmose said in a press statement by West Copenhagen Police.