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Authorities have reportedly smoked out tour buses carrying Rihanna's entourage  -  and marijuana. 

TMZ.com says ten buses were stopped at the border between Michigan and Canada where inspectors uncovered the herbal drug on one passenger.  Rihanna was not on any of the buses. 

According to TMZ, inspectors brought in drug-sniffing dogs when inspectors caught a whiff of marijuana on one of the buses.  The hounds apparently sniffed out the one passenger who was cited with a civil penalty.  

Rihanna just wrapped up a two-night stand in Toronto on Monday and Tuesday.  She is scheduled to perform in Detroit on Thursday and Chicago on Friday. 

Rihanna has also rescheduled the Baltimore concert she missed last week due to illness.  That show is now set to take place on April 24th.