The FBI is again warning the public to beware of calls from the FBI.
The Los Angeles FBI field office told NBC News they have been receiving dozens of reports from people saying they were contacted by scammers using an FBI phone number and demanding money. The callers claim that the people are under investigation and will be arrested if they don't pay up immediately.
The victims see a real FBI number on their phones, because the scammers are "spoofing" — using technology to mask their real phone numbers and send the FBI number to caller ID instead.
FBI satellite offices throughout California are receiving similar complaints.
Earlier this year, NBC News reported that the FBI's Denver field office had issued a public warning after scammers using the same scheme called victims in northern Colorado. The callers were spoofing the phone number of an FBI office in the western part of the state.
Related: The FBI Doesn't Phone You and Ask for Money. Hang Up.
The phone numbers of field offices in Missouri, Pennsylvania, Texas and Virginia also have been used to target callers in their respective states.
It's not immediately clear how many people were victimized in the latest wave of calls in the L.A. area given that many victims do not report calls or are embarrassed if successfully scammed. But an FBI spokeswoman told NBC News that in Los Angeles, the bureau had received dozens of complaints about phone scammers.
The FBI strongly suggests that given the rushed and threatening nature of the calls, victims should hang up on the scammers right away and contact their local FBI field office.
Last year, the FBI's St. Louis, Missouri Division issued a news release warning the public about a similar spoofing scam in which a fake FBI agent told victims the bureau was investigating a tax violation. Scammers spoofed numbers from the FBI's offices in Eastern Missouri to call victims in Western Missouri.
"These are old scams that keep evolving with a new twist," said William Woods, special agent in charge of the FBI St. Louis Division. "Just remember, the FBI does not call or e-mail private citizens to demand money or threaten arrest."