SAN JUAN, Puerto Rico (AP) — Federal authorities on Monday arrested seven people including a union leader and various dock workers accused in a $1.2 million extortion scheme that targeted shipping companies.

U.S. Attorney Stephen Muldrow said the scheme began in 2005 and affected local and foreign commerce, including shipping between Puerto Rico and the U.S. and British Virgin Islands.

He said suspects at three docks in the capital of San Juan are accused of illegally extorting small shipping companies and threatened to stop loading and unloading goods if the payments weren’t made. The payments demanded varied by weight and sometimes ranged from $10,000 to $20,000 a month, Muldrow said.

The suspects face charges including conspiracy to violate the RICO Act, extortion and money laundering.

“Breaking the law cannot be the way to do business in Puerto Rico,” said Joseph González, FBI special agent in charge of the San Juan office.

Local and federal authorities were part of the five-year investigation, with some wearing shirts at a press conference that read “Pier Pressure” in reference to the operation.