By BDC News
Police spokesman Lars Bystrom said, "a small amount of drugs and a stun gun were found when officers raided the empty bus parked under the Globen concert venue in Stockholm," where the singer was performing on Wednesday.
He declined to identify the drug, saying it had been "sent to a laboratory for an analysis".
No-one has been arrested.
Police acted after smelling marijuana coming from inside the bus when it was parked outside the hotel where the singer was staying.
The drug squad was alerted and searched the bus after it carried a group of people to the concert venue.
Police say there are no suspects, and won't be taking the matter any further.
Bieber is in Stockholm on the European leg of his Believe world tour.
When he was in London in March the Canadian singer caused controversy when he was late on stage for a concert at the 02 arena.
A few days later he made headlines again when he confronted photographers outside his central London hotel.
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