Bieber was not present when border authorities searched the bus, which was crossing into the U.S. from Canada when the substance was discovered. A small amount of marijuana and drug paraphernalia was seized, and the bus driver was issued a civil penalty.
This is the second time authorities have found illegal substances on one of Bieber's buses. In April, law enforcement raided the pop star's bus in Sweden after noticing a "strong smell" of marijuana. A small amount of pot and a taser were found..
Check out Bieber's latest bad behavior here.