A smuggling ring brought narwhal tusks from the Canadian Arctic into Maine in a trailer with a secret compartment and then illegally sold them to American buyers, according to an Associated Press article.

Andrew Zarauskas, of Union, N.J., and Jay Conrad, of Lakeland, Tenn., will be arraigned in Bangor, Maine, next week on 29 federal smuggling and money laundering charges each, the article says.

For nearly a decade, two Canadians smuggled the whale tusks into Maine and shipped them via FedEx to Zarauskas, Conrad and other unnamed American buyers, according to an indictment, AP reports. Narwhals are known as the “unicorns of the sea” for their spiral, ivory tusks that can grow longer than 8 feet. While the tusks can sell for thousands of dollars each, it’s illegal to import them into the U.S.

The court document doesn’t specify how much money was involved, but it says that the Canadian sellers received at least 150 payments from tusk buyers, AP reports.

Todd Mikolop, the prosecutor of the case for the environmental crimes section of the Department of Justice, says that “The conspiracy we’ve alleged was over a period of 10 years, so there appears to have been enough of a market to support that length of conduct.”

Narwhals live in Arctic waters and are harvested by Inuit hunters for their meat, skin and tusks, the article says, and tusks are sold to buyers who want them for display purposes or to turn into jewelry. Tusks range from 3 feet to more than 8 feet, and typically sell for $1,000 to $7,000 each. While tusks can be shipped worldwide, trading companies such as Furcanada refuse to ship to prohibit imports, including the U.S., the U.K. and Australia.