A nervous neighbour called police to warn that "a masked thief clad entirely in black" had jumped down from the balcony of the house next door.
But reports surfaced this week that the thief was no thief. The leap was simply a ritual part of advanced ninja training.
One of the neighbour's sons had decided to devote himself to wall-scaling and acrobatic tricks – while dressed as a ninja, naturally.
"The patrol went there and met the person who had called. But we quickly realized that there was no break-in. It was just the boy practicing," Tove Hägg, police spokeswoman, told newspaper Expressen.
Hägg noted that the police were accustomed to such odd operations, and that she didn't even raise an eyebrow.
"Once we had a man who had a parrot stuck on his head," she recalled. "This time I was just glad that it wasn't a break-in."
The young ninja said he was frightened at first when the police knocked on the door, but quickly realized there was no problem. He noted that he will certainly keep climbing and leaping – but that he might not keep wearing the ninja outfit.
The police wouldn't mind if he did, however.
"Exciting day on the job – and what a great outfit!" the police wrote on their Facebook page after the incident.