A Canadian college student caught at a border checkpoint with 51 live turtles in his pants has pleaded guilty to six smuggling charges in US District Court, reported ABC.

According to AP, Kai Xu, 27, would order turtles online and travel to Michigan to pick them up and then ship them to China or return with them to Ontario, Canada. He pleaded guilty to six crimes in federal court in Ann Arbor and faces a maximum penalty of 10 years in prison.

It is illegal to export wildlife from the US without a permit from the government.

Xu “regularly deals in turtle shipments worth $30,000, $80,000 or $125,000,” Sara Woodward, assistant US attorney, said in a court filing. “In China, the turtles he smuggles are worth two to three times the amount he pays here.”

Matt Borgula, defence attorney, declined to comment after the guilty plea.

Xu has been in custody since his arrest in suburban Detroit in September 2014. He describes himself as an engineering student at the University of Waterloo in Waterloo, Ontario, although the university said he wasn’t enrolled at the time of his arrest.

In summer 2014, weeks before his arrest, Xu was under surveillance in Detroit. After picking up a box at a United Parcel Service site, he hid behind trucks and emerged with “irregularly shaped bulges” under his sweat pants, wildlife agent Ken Adams said.

Xu returned to Ontario but was stopped by Canadian border authorities who found 51 live turtles taped to his legs, including box turtles and terrapins.

Despite the bust, “he did not cease smuggling turtles. He did not even slow down,” said Ms Woodward.