“The fraudsters appeared to do a very thorough job of both vetting the background of their fictitious identity, so knowing a lot about the individual they’re representing themselves to be, and also a thorough job on vetting the work done by many of the defrauded victims,” Mr. Hemmen said in an interview with The New York Times.

“Please be advised this is an ongoing scam, and individuals who have plans to travel to Indonesia for a job opportunity in the entertainment industry should perform additional research and proceed with caution,” the F.B.I. said in a news release on Monday. The agency has an online form for people who think they might have been a victim of this swindle as far back as 2013.

Nicoletta Kotsianas, senior director of K2 Intelligence, an investigations firm with headquarters in New York, said in an interview Monday that her company believed that the fraudulent offers were being made by an individual. K2 has been looking into the case since 2017 on behalf of some industry executives who say they have been impersonated.

As for the individuals being defrauded, if they are looking for work and have contact information available online, they can be easy for criminals to find, Ms. Kotsianas said.

While the F.B.I. would not provide estimates of how many people had been duped or how much money they had lost, Ms. Kotsianas said K2 had spoken to about 100 victims . Some have lost around $3,000, which typically accounts for airline tickets and an Indonesian driver, she said. In other cases, the losses have extended to $150,000 for those who made multiple trips to Indonesia and believed they were deeply involved in projects that later proved to be nonexistent. On average, she added, the victims she knew about had lost $15,000 to $20,000.