Twenty-five Canadians have been charged with being part of a scheme to defraud hundreds of seniors across the United States, according to U.S. federal prosecutors.

The conspirators called older adults and posed as their grandchildren in need of bail money after a fake arrest, federal prosecutors said.

A group of 25 Canadians who go by code names like “Muscles,” “Truck,” and “Keanu” have been indicted for a “grandparent scam” that targeted U.S. seniors, according to the U.S. District Attorney’s Office in the District of Vermont.

Federal prosecutors allege those charged claimed a relative, usually a grandchild, needed money for bail after an arrest.

Canadians are charged in connection to scam that cost American retirees $21 million over a three-year period, according to authorities.