As Justin Bieber continues the European leg of his tour -- leaving a trail of abandoned monkeys and painful guest book signings in his wake -- it seems the stench of pot coming from his tour bus in Stockholm caught the attention of Swiss authorities and caused them to have a closer look-see.

Based on information from a representative for the Stockholm PD (via TMZ), an officer smelled ganja emanating from the Biebs' bus on Wednesday night (April 24). He then called the narcotics unit and gained a search warrant.

The bus was searched while it was parked at the arena where Justin was performing that evening. No one was on it at the time.

Swedish newspapers report the found items included a small amount of weed and a taser (which one needs a permit to have), but since it's unclear who owned them, no one was arrested or charged.

Currently, all theories point to "anyone," because that's kind of how Justin and his posse roll these days. To wit: Bieber was spotted hours prior to the "raid" with Lil Za -- the same pal with whom he was photographed smoking back in February.