A payment processing company based in Vancouver has been named by the U.S. attorney general in an international mail and lotto fraud case.

The PacNet Group has a lengthy history of money laundering, according to a statement from the U.S. Treasury Department on Thursday. None of the allegations have been proven in court.

PacNet offers payment processing services including multi-currency payouts, check cashing and international credit cards. The company has offices in Vancouver, Ireland and the U.K., and subsidiaries or affiliates in 15 other countries, according to the Treasury.

The U.S. Department of Justice accuses the company of being a "significant transnational criminal organization," with a nearly 20-year history of "knowingly" processing payments related to scams.

PacNet's processing network helps to prevent detection of fraud, the Treasury said.

"Every year Americans receive tens of millions of fraudulent solicitation letters, and many of these letters, for example, falsely claim that the recipient has won cash or valuable prizes," Attorney General Loretta E. Lynch said at a news conference.

"In order to collect these benefits, the letters say, the recipient need only send in a small amount of money for a processing fee or taxes."

The perpetrators are often targeting the elderly and those in vulnerable financial situations, Lynch said.

The Treasury said scammers arrange for those payments to be sent through PacNet, then the company takes fees and commission and passes the funds on to scammers through wire transfers. The process of using PacNet as a "middle man" helps obscure the link between scammers and their victims.

PacNet has received "many notifications" about the fraudulent activity of its clients, but "continues to knowingly process checks" on behalf of companies involved in mail fraud, the Treasury said.

The company has been in trouble in the past, having to refund money received as part of a psychic scam in 2009. It also received subpoenas from Iowa regarding a scam in that state in 2014.

As a result of the investigation, 12 executives and directors have been identified as being involved in the scam. Three of the dozen, Marie Boivin, Mary Ann Driscoll and Rosanne Day, are based in Canada.

All U.S. residents are prohibited from engaging in transactions with the individuals named by the Treasury. Their property in the U.S. has been blocked, and the funds in a PacNet bank account have been seized.

In addition to PacNet, several other businesses are under investigation. People from Turkey, Switzerland, France, the Netherlands, Singapore, India and the U.S. are facing charges, and several businesses have been named in the case.

A request for comment from PacNet has not yet been returned.

With files from CTV News' Tom Walters and CTV Vancouver's Mi-Jung Lee