The pop star was not present during the police search.
Ten of Rihanna's tour buses were stopped around 9 a.m. Wednesday morning en route to Detroit from Toronto, leading inspectors to find marijuana on one of them.
The buses were stopped at the Ambassador Bridge located near the border between Detroit and Windsor, Canada, according to TMZ.com.
The celebrity news site also reported that after noticing the scent of marijuana, the inspector called for a secondary search of the vehicles. Drug sniffing dogs were brought on board, where they quickly discovered that one of the passengers was in possession of a small amount of marijuana.
"The canine did alert on quite a few of the buses, but it was only that small amount found," Kris Grogan, who is a spokes for U.S. Customs and Border Protection told The Daily News.
Rihanna, though not shy about her love for the ganja, was not on any of the busses at the time.
The unnamed passenger was cited with a civil penalty.
BET.com is your #1 source for Black celebrity news, photos, exclusive videos and all the latest in the world ofhip hop and R&B music.
Click here to subscribe to our newsletter.
(Photo: Dominic Chan/WENN.com)