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DETROIT (AP) — U.S. border agents found marijuana on a bus with singer Justin Bieber's tour as it crossed into Detroit from Windsor, Canada.

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The Detroit Free Press reports that U.S. Customs and Border Protection spokesman Ken Hammond confirms that the bus was stopped Sunday as it attempted to enter the U.S. on the Ambassador Bridge.

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The singer was not on the bus at the time and performed later that night at Joe Louis Arena.

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Hammond says a police dog indicated the presence of drugs on the bus and that drug paraphernalia and a small amount of marijuana were found. He says the bus driver was cited and the bus and its passengers were allowed to go.