Police departments across Utah are warning people not to answer calls from the 473 area code.
Police said Utahns across the state are answering their phones without recognizing the 473 number, which comes from Grenada, Carriacou or Petite Martinque.
When they answer, they hear a commotion or sounds of moaning or someone in distress before the caller abruptly hangs up.
Utah Department of Public Safety spokesman Dwayne Baird said residents are reporting that regardless if they call back, they're getting a $19.95 charge immediately tacked on to their cell phone bill.
He said the scammers are able to use Utahns' basic cell phone information gathered when they answer to add the charge to the bill.
Police said they didn't know what was prompting the charges, but Fox 13 reported the number is linked to a phone sex business.
Baird said anyone who doesn't recognize a phone number on their caller identification should just ignore it.