Authorities have arrested four people in connection to "virtual kidnappings" over the last six years. According to The Associated Press, the suspects were involved in a scheme that used fake “telemarketers” to trick immigrants into paying ransoms for relatives who weren’t even missing. The virtual kidnappings resulted in nearly $500,000 being conned from people in the U.S., mostly in the Washington, D.C., area.  

“They would just randomly run through a sequence of numbers, like 1 to 100,” Daniel Page, assistant special agent in charge of U.S. Immigration and Customs and Enforcement’s Homeland Security Investigations unit in San Diego, told The Associated Press. “They’re just like your professional telemarketer. They have a script. ‘You need to pay this money. If you don’t, something’s going to happen.’”

The arrests were made after an investigation that began in 2011 involving a real kidnapping that turned into a virtual kidnapping. That year, a woman in Fresno, Calif., wired $2,500 to a Walmart in San Diego to free her brother-in-law, who was beaten and held hostage for several days in Tijuana, Mexico.

After the man was released, the Fresno woman got another phone call saying her brother-in-law was again a hostage and that she would need to pay a ransom for his freedom. Knowing there was no way her brother-in-law could have been missing, she called the police.

The encounter with the virtual kidnappers eventually led to the arrest of a married couple outside a 7-Eleven store in California. Both of them pleaded guilty to charges of money laundering. The investigation into the virtual kidnappings continued, and four more people were arrested on Thursday.

They were 63-year-old Ruth Graciela Reygoza of Chula Vista, Calif.; 23-year-old Juan Rocha and his 25-year-ld brother Adrian Rocha, U.S. citizens who live in Tijuana; and 42-year-old Maria del Carmen Pulido, who lives in Los Angeles. They are scheduled for a detention hearing this Thursday, according to The Associated Press.

Virtual kidnappings have become common in many parts of South America and Mexico, where callers in Tijuana using San Diego telephone numbers dial up to 5,000 random numbers a day and demand that money be wired. In exchange, the callers say they’ll release one of the person’s relatives who is being held hostage. Callers target immigrants who may have family trying to come to the U.S. They focused on D.C. because of the large Central American immigrant population there.

Calls rarely lead to any ransoms being paid, mainly because callers have no idea if the person on the other end is an immigrant with family trying to come to the U.S. When someone does take the bait, they could end up paying between $1,000 and $3,000, according to Business Insider.

According to a New York Times article from 2008, many of the callers are thought to be in prisons. Authorities believe hundreds of different criminal gangs are involved in various telephone cons. They’ve even made ransom demands over text messages.