Justin Bieber

Authorities found marijuana on one of Justin Bieber's tour buses in Detroit on Sunday, The Detroit Free Press reports.

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.

Justin Bieber's downward spiral: A timeline of bad behavior

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.