A Canadian man is facing a maximum of 20 years behind bars and a possible fine of up to one-million dollars U-S for trying to export fentanyl products and other synthetic drugs.

Karl Morrison, a 59-year-old from Kitchener, Ontario pleaded guilty to attempting to export the drugs from China into the US. Morrison’s wife, Sorina Morrison, also pleaded guilty to failing to report the crime to law enforcement and could face up to three years in prison and a maximum fine of $250 thousand dollars US.

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Fentanyl is an opioid-based pain killer roughly 100 times stronger than morphine, which can be fatal even in tiny doses.

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The U.S. Attorney’s office says the couple crossed into the U.S. and collected four packages. The initial criminal complaint against the Morrisons filed to the court says they crossed stating that they intended to go shopping at an outlet mall.

A release sent out Thursday after the couple pleaded guilty says they instead bought shipping supplies and repackaged the contents of the parcels into new envelopes that they paid to ship back to Canada, including one to their home address.

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Sorina Morrison claimed she was sending cinnamon butter back home, but U.S. prosecutors say that the parcel was filled with more than 500 grams of powder that contained pentylone. The other packages contained about 6.5 grams of powder containing furanyl fentanyl.

“The couple discarded the Chinese shipping labels of the original packages in various garbage cans around Niagara County to cover their tracks,” the U.S. Attorney’s release says. “They also obtained the name and address of an unsuspecting citizen in Niagara Falls to use as the return address on the packages they shipped to Canada, to further disguise the origin of the illegal contents.”

The office says all four of the packages were intercepted by law enforcement before they could be sent to the intended address, and the couple was arrested as they drove back across the Lewiston Bridge toward Canada.

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Before pleading guilty to the lesser charges, the couple initially pleaded not guilty to charges of conspiracy to import and export controlled substances, and attempting to export controlled substances.

The initial criminal complaint says Karl Morrison told border officials that his son, Albert, had recently learned of his UPS mailbox in the U.S. and asked if he could have packages from Japan and China shipped there, which he agreed to.

Karl Morrison said he picked up three packages for his son, which were from China, on Oct. 15, 2016, and said he knows his son is a drug abuser, the complaint says.

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“Albert had explained to Karl what he was having sent to the mailbox in Niagara Falls,” the complaint states. “Karl Morrison said he did not understand everything his son was telling him, but that Albert said the names of the things he was sending started with ‘F’ and ‘U.”‘

The complaint says Karl Morrison also told authorities he and his wife mailed the packages to their son because they didn’t want to carry them across the border, and he used random addresses on the packages being mailed to Canada because he didn’t want them to be connected to his UPS mailbox.

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The Morrisons are scheduled to be sentenced in a Buffalo, N.Y., court in July.