WASHINGTON – One man, alarmed at the thought that hackers might attack his computer, shelled out $14,990 to a company promising a “fix” that would keep it safe.

Eight months later, the 68-year-old from Hawaii mailed the same company a check for $24,999 more. And he kept paying. All told, the unnamed man, who suffers from dementia, sent about $356,000 in checks and wire transfers, unaware that the computer security alert was part of a network of elaborate scams that the government says cost the nation’s elderly and infirm hundreds of millions of dollars over the past year alone.

The case is part of a heartbreaking archive of court documents filed in just the past year, charging more than 200 suspects with trying to swindle 2 million Americans, most of them elderly.

Federal authorities said the illicit operations, some based in the United States and others scattered across the globe, looted seniors of nearly $1 billion. The charges brought in the past 12 months, the second such enforcement campaign in as many years, represents the largest of the federal sweeps against elder fraud.

“Crimes against the elderly target some of the most vulnerable people in our society,” Attorney General William Barr said Thursday. He said the Justice Department will intensify its efforts to target those cams, promising to mount an “all-out attack.”

The broad enforcement effort, involving the FBI, Postal Inspection Service, Secret Service and the Department of Homeland Security, identified suspects in Canada, The Cayman Islands, Costa Rica, Jamaica and Poland.  The far-flung networks involved groups of varying sizes, from small boiler-room operations to organizations involving as many as 500 people who worked day and night shifts calling potential targets throughout the United States, authorities said.

New attention was brought to the problem earlier this year when former FBI and CIA Director William Webster acknowledged that he had been targeted in a lottery scam.

Webster, 95, went straight to the FBI after he was directed to pay thousands of dollars to cover taxes on the phony multimillion-dollar prize.

This year, a Jamaican man was sentenced in the case to nearly six years in prison.

The most prolific of the recent schemes, however, have involved phony computer security alerts, which prompted a costly response by the elderly Hawaii victim, who was identified in court documents by the initials, “S.K.”

Typically, suspects trick victims into providing remote access to their computers, believing that the so-called “technical support” will plug gaps in security. Last year, the Federal Trade Commission received more than 142,000 complaints involving the computer scams.

In another case involving a California man, a telemarketer directed the 74-year-old retiree to make a series of payments to install “updated security software” to guard against hacks.

During a two-year period, the victim made payments totaling more than $500,000, some of it routed to a bank in New Delhi.

, USA TODAY Published 12:05 p.m. ET March 7, 2019 | Updated 4:16 p.m. ET March 7, 2019