AceShowbiz -

A search inside Justin Bieber's tour bus turned up marijuana when authorities stopped it as it passed along the border of Michigan and Canada, right on Ambassador Bridge. A drug-sniffing dog was able to detect the presence of drugs on board.

According to Chief Customs and Border Protection Officer Ken Hammond, weed and drug paraphernalia were subsequently uncovered from the search. After the items were seized, the driver was issued a citation and the passengers, who did not include Bieber, were eventually released.

This is not his tour bus' first brush with a drug-related controversy. Back in April, it turned up a "small amount" of narcotics and a taser after it was searched in the Globe Arena in Stockholm, Sweden where Bieber was performing a leg of his "Believe" world tour.

A month after that, Bieber was spotted smoking weed while riding on a segway inside his Calabasas gated community which outraged his neighbors as he apparently smoked the joint right in front of the neighborhood kids.

As for the Ambassador Bridge raid, Biebs follows in the footsteps of another popular artist, Rihanna, whose tour bus also encountered a similar incident back in March. A search of RiRi's entourage of ten tour buses was able to uncover cannabis, found in the possession of one of the passengers which also did not include the artist.