Two explosive devices detonated at the scene, police said. The facade and gate were damaged, but no one was physically injured.
Later in the evening, suspicion arose against a boy under the age of 15.
"We suspect he was involved. He was taken home to his guardian," said police spokesman Nils Norling.
"For reasons unknown to me, the social services department in this case has not been able to take him in."
A 25-year-old man was arrested overnight on suspicion of aiding and abetting the destruction of public property.
