Two dozen Canadian nationals were charged for their alleged roles in a scheme that targeted seniors by posing as relatives asking for emergency bail.

Nearly two dozen people, including 10 from the West Island, have been arrested and are wanted in the U.S. where they are alleged to have been part of a large-scale grandparent scam. On Tuesday, police officers from the RCMP and Sûreté du Québec fanned out in and around the Montreal island and other parts of Quebec and arrested 23 people sought in an extradition request from the U.

The 25 Canadians are accused of calling seniors in over 40 states, pretending to be their grandchildren and asking for bail money. Authorities warn such scams are getting increasingly sophisticated.

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