FALLS CHURCH, Va. - For the victim, a 78-year-old man from Annandale, it started with an effort to find some companionship. He created an account on a social network called iFlirt, then made contact with someone identifying herself as a widowed woman in her 30s who seemed interested.

As the online relationship grew, though, the scam started to emerge. The woman, who claimed to be from New York, said she was arrested while traveling to Germany to retrieve an inheritance of gold bars, and needed money to make bail. The man paid it, only to get another message that she was arrested a second time and needed even more money.

In the end, the Annandale man, who is not identified in court papers, got taken for well over $500,000, the latest victim in a growing trend known as romance fraud.

Romance scams reached a record high in 2021, increasing by nearly 80 percent from 2020, according to a report from the Federal Trade Commission. During the past five years, victims have lost more than $1.3 billion to such scams, the FTC said, more than any other category of fraud the agency tracks.

Two of the people who scammed the Annandale man were scheduled to be sentenced Feb. 18 in federal court in Alexandria. Ghanaian nationals Linda Mbimadong and Richard Broni played relatively minor roles in the scam. Prosecutors describe them as “money mules” who never made contact with the victim themselves but helped receive and launder the money in return for a 5 percent to 10 percent cut of the proceeds.

Prosecutors estimate that the scheme targeted multiple victims and raked in more than $42 million, much of it going go Ghana, where the scam was headquartered.

In memos ahead of the sentencing hearing, Ms. Mbimadong and Mr. Broni, who were living in New York at the time of their arrest, apologized for their actions.

“I have to express my ugly truth. I was selfish, ambitious and greedy for success,” Ms. Mbimadong wrote.

Jessica Aber, U.S. attorney for the Eastern District of Virginia, is prosecuting the Annandale man’s case. She said large numbers of romance scams go unreported because victims are embarrassed that they fell for tales like the one the defendants in this case spun, around widowed royalty and inheritances of gold bullion. But she said the scammers are sophisticated and patient in their approach, building rapport with targets over a matter of months before making their move.

“These fraudsters know exactly how to play on people’s emotions,” Ms. Aber said in an interview. “They use third parties to try to validate the stories that are being spun.”

Authorities take it seriously when complaints are made, Ms. Aber said. Her office has prosecuted multiple cases of romance fraud in recent years.

Scammers are based both domestically and internationally, she said. Sometimes fraudsters spin exotic tales of international intrigue; other times, the approach is more mundane.

Richard Dorpe, a Ghanaian national, portrayed himself as a balding 57-year-old white man from Virginia Beach named “Jerry Linus” on the “OurTime” senior dating website. He conned a 68-year-old widow from Chesapeake out of more than $300,000, as well as items including clothes, a computer and jewelry. When she ran out of cash, she took out a home equity loan.

Mr. Dorpe was sentenced to more than three years in prison last year by a federal court.