Charles Bennett had already lost his home and moved into a trailer to pay the scammers who had taken over his life. Soon he was hiding there in the dark, told in a late-night phone call that he was about to be arrested over unpaid bills.

The 85-year-old Massachusetts man would be stopped from selling the trailer by a social services investigation, but he lost all control over his finances. Even then, he starved himself so he could hand over his food allowance to the scammers. He remained convinced he'd won millions in prize money and would soon live lavishly, if only he first paid a few fees.

Bennett fell victim to a "Jamaican lottery scam," a scheme so pervasive that it appears in law enforcement task force acronyms and in reggae songs. Callers promise winnings in exchange for the payment of taxes or fees that keep rising, with the scammers sometimes threatening violence when their marks express reluctance to pay.

Bennett's scammers were eventually caught and prosecuted in federal court in Alexandria, Va., but that took many years. By the time the final defendant, Tessicar Jumpp, 34, was extradited from Jamaica and sentenced to six years in prison this summer, Bennett had been dead for nearly two years. Jumpp was the last of seven family members convicted of together scamming elderly people out of about $750,000.

The case was prosecuted in Northern Virginia because at least one of the 10 confirmed victims lived there, authorities said.

Law enforcement officials say the scam is among the most lucrative of various phone-based schemes targeting vulnerable elderly people, and one that for a long time has gone under-prosecuted. The lead perpetrators are overseas, the money is usually sent in small chunks, and the victims may be uncooperative or confused, making it difficult and time-consuming to build cases. Gene Rossi, a former federal prosecutor who worked on the investigation in Alexandria, said it was a struggle to get the necessary resources.

"There are probably hundreds of Ms. Jumpps out there in Jamaica because it's so easy," he said. "I think the Justice Department should take it up a notch and focus more on this than on prosecuting people who are selling marijuana."

When prosecutor Zachary Terwilliger took charge of the office of the U.S. attorney for the Eastern District of Virginia, the Jamaican lottery investigation was ending. But he said the Justice Department is committed to fighting the problem — in part spurred by legislation he helped craft while working on the staff of the Senate Judiciary Committee. The legislation mandated elder justice coordinators within the Justice Department and stiffened penalties.

"The devastation that this economic harm causes people later in life — the stress, the anxiety. . . . It can be catastrophic," Terwilliger said. It's "absolutely one of our priorities."

He said that with an aging mother-in-law and 7-year-old child, he is part of a "sandwich generation" helping to take care of both.

For older people who fear becoming a burden on their children, these scams offer the promise of a magical escape — the money to pay for every need, and a new friend to call at any moment.

Assistant U.S. Attorney Clare Hochhalter, whose office in North Dakota has prosecuted more Jamaican lottery scammers than any other jurisdiction, hopes the new focus is effective.

"People in my own office didn't care, because everybody gets tricked," he said. That attitude, he argued, undervalues not just the financial devastation caused by the scams but also the potential risks.

"Many of the victims will remain victims for years and are subject to control of these anonymous professionals," Hochhalter said.

The prosecutor said he worries about the damage a violent group or even enemy state could inflict with that kind of control over elderly Americans. "We have victims who have received anonymous packages, are instructed not to open them and deliver them — and they do."

In its investigation of the Jamaican lottery case, his office has created a template he hopes others will follow, after tracing one victim to at least 100 others through a network of 27 scammers. Subsequent investigations have focused on the sellers of "lead lists" that identify lucrative targets — elderly people who live alone and have responded to lottery solicitations.

Bennett had lost his son years earlier in a car accident; when various scammers began calling, he was taking care of his wife, who had Alzheimer's. The calls continued after she died, telling him that his wife had had an insurance policy on their son and that he could access it for a fee.

His niece Sandra Hudson said the isolation crippled him. He fell for one scam after another; he lost $50,000 to the group charged in Alexandria, but that was only a piece of the life savings he lost.

"He would admit it was a scam, and then it was like it was forgotten," Hudson said. When her son, a federal agent, tried to explain to him why a purported government document was fake, Bennett cut him out of his life.

"They've lost their life savings and they can't accept that they lost their life savings," Frank Gasper, the lead FBI agent on the North Dakota cases said of scamming victims. "You can't go back to work if you're in your 80s. If they accept the fact that they lost the money, then they've lost all hope."

Gasper fielded many elder fraud complaints before he got the one that launched the North Dakota Jamaican lottery investigation: a woman in a small rural town who lost her life savings of over $300,000. Because of the amount of money involved, and because it went by check to a woman in Florida, he knew he could make a case. Often, money is funneled through other victims, which makes it harder to trace.

It is also difficult to extradite people to the United States for prosecution. The process requires not just an affidavit from a law enforcement agent but signed statements from witnesses or co-conspirators.

The perception in Jamaica is that "it's worth it, it's easy to get away with," Assistant U.S. Attorney Samantha Bateman said at the August sentencing of Jumpp, the only one of Bennett's scammers extradited from Jamaica. (Another was arrested at the airport traveling to the United States; he is serving a 10-year sentence. The others lived in the United States.)

Trying to get any money back is even harder, although Gasper has flown to Jamaica with victims to seize assets through civil court proceedings there. "They spend the money," he said. "They have these big parties and they'll buy champagne and then they'll wash a car with champagne. They'll have a contest, whoever burns the most amount money gets to play the next song. That's where the money goes."

Jumpp was not so profligate. Her attorney said she used the money only to avoid eviction herself, and quit the scam out of guilt long before her arrest.

"I couldn't do it anymore because of how it felt inside," Jumpp said at her sentencing. "I made a terrible and selfish decision. What I did has eaten against me for four years. I had sleepless nights. It was a horrible, horrible crime that I committed."

She said when she heard in court that one victim who lost $300,000 was a cancer survivor, she thought of her own mother's cancer diagnosis.

"There is such a thing as karma," she said. "What you sow is what you reap."