The Federal Bureau of Investigation (FBI) is advising anyone who receives a call from a woman screaming for help to hang up, as the call is part of a decades-old kidnapping scam.

The agency warned consumers on its website of a virtual kidnapping scam where callers lure victims into paying ransoms to free “kidnapped” family friends, only to tell them that nobody has been kidnapped.

The FBI said it has been tracking the calls between 2013 and 2015, which have been traced to Mexican prisons.

A typical scam call begins with a woman screaming, “Help me!” before blurting out a name and asking if that person is okay. The caller then informs the victim that the person has been kidnapped and will be harmed if the victim does not pay ransom promptly.

The scammers try to keep their victims on the phone so they do not call their loved ones and are successful when victims are not aware of their loved ones’ whereabouts. The FBI said that the scammers typically demand that victims wire small-dollar amounts to Mexico.

The scammers typically request that their victims wire less than $2,000 because federal law limits wiring large sums of cash across the border.

The agency added that the scammers mostly targeted Spanish-speaking victims in the Los Angeles and Houston areas.

According to a recent investigation, the agency found that more than 80 people who fell victim to the scam in California, Minnesota, Idaho, and Texas forked over $87,000 in ransom money.