Four accused scam artists, three from Southern California and one from suburban Chicago, were charged in an alleged “pig butchering” scheme that bilked victims out of more than $80 million, officials said Thursday.

The defendants would cold call victims via dating apps and other social media platforms to “slowly gain their trust, eventually introducing the idea of making a business investment using cryptocurrency,” according to a statement by federal prosecutors in Los Angeles.

U.S. authorities call this a “pig butchering” scheme, loosely translating the crime’s foreign language description of building a mark’s confidence before going in for the kill of stealing money.

These “unsolicited messages or calls” were often presented as innocent “wrong number” contacts before striking up a friendship with victims, federal authorities said.

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The government named four defendants, Lu Zhang, a 36-year-old woman from Alhambra, California, and three male co-defendants — Justin Walker, 31, from Cypress, California, Joseph Wong, 32, of Rosemead, California, and Hailong Zhu, 40, from Naperville, Illinois.

They were all charged with conspiracy to commit money laundering, concealment money laundering and international money laundering, officials said.

It wasn’t clear by Thursday afternoon if they had hired or been assigned defense lawyers yet to speak on their behalf.