DETROIT (AP) — A Canadian cab driver who made extra money by steering desperate immigrants to a railroad tunnel under the Detroit River was sentenced Monday to 16 months in a U.S. prison.

Juan Garcia-Jimenez, a 53-year-old Canadian citizen who is a native of Guatemala, wept in federal court. Besides a prison sentence, he was fined $8,680– the amount paid by six people who were caught last year when they emerged on foot on the Detroit side of the tunnel.

The 1.6-mile tunnel is used by cargo trains moving between Ontario, Canada, and the United States. Assistant U.S. Attorney Susan Fairchild said it’s risky: A walkway is only 17 inches wide and in poor condition.

“They just walked right through the tunnel, which is a very dangerous thing,” said Kris Grogan, a spokesman for U.S. Customs and Border Protection.