Police in Umea said they became suspicious after a man who appeared to be loitering outside of the Gamla Fangelset hostel late Friday eventually used a door code to enter the building, and a sound that resembled a woman's high-pitched screams was heard shortly after the man went inside, Swedish news agency TT reported Wednesday.
"They thought somebody in there was in distress and made a decision to raid the premises," police spokesman Peder Jonsson said.
However, when the police broke down the door and entered the building, they discovered members of a South African choir cooking food in the hostel's kitchen.
A representative from the hostel soon joined the singers and explained to police that the high-pitched sound had been a female member of the choir practicing for an upcoming performance at the Norrlandsoperan opera house.
Police said the officers left the building after determining that no crimes had taken place.