Federal authorities Wednesday escalated their assault on the double-barreled crime of identity theft and tax fraud, arresting 30 South Florida suspects — including a Miami Gardens man facing a murder trial — on charges of filing fake returns totaling millions of dollars.

Prosecutors in Miami unveiled charges against a total of 40 defendants accused of stealing the personal information of roughly 54,000 people and using it to file fraudulent income-tax refund claims with the Internal Revenue Service.

One defendant obtained the Social Security numbers of 26,000 people by searching a public database, according to court records. A separate group of defendants filed phony returns in the names of 5,000 people — nearly all of whom were dead — and received $6 million in IRS refunds.

“Identity theft and tax-refund scams are nothing less than a tsunami of fraud that is barreling toward us,” U.S. Attorney Wifredo Ferrer said at a news conference, pointing out that gang members, drug traffickers and violent criminals have become the face of “one of the fastest-growing and most pervasive problems in the United States.”

Among those arrested Wednesday: Lineten “Link” Belizaire, who was charged in August with the Lauderdale Lakes killings of two women and a baby. He had been out on bond awaiting trial in Broward County.

Belizaire, 21, of Miami Gardens, has pleaded not guilty in the January shooting deaths of Octavia Barnett, 21; Barnett’s roommate, Natasha Plummer, 25; and Plummer’s 6-month-old boy, Carlton Stringer Jr.

Ferrer said the murder prosecution was unrelated to Belizaire’s federal indictment, which accused him and three partners of submitting hundreds of bogus tax refund claims totaling $1 million and requesting that payments be made on pre-paid debit cards over the past year.

Ten of the 40 defendants indicted remained at large, officials said.

Wednesday’s takedown by a new South Florida task force — involving the IRS, FBI, Secret Service, U.S. Postal Inspection Service and local police departments — follows a Justice Department edict on Oct 1. It gave authorities at the local level greater leeway to pursue tax-fraud offenders who swipe other people’s identities to fleece the federal government.

Victims have ranged from South Florida police officers to Holocaust survivors to U.S. Marines stationed in Afghanistan.

“We know that identity theft and tax fraud has turned the lives of taxpayers upside down,” said Jose “Tony” Gonzalez, special agent in charge of the IRS’ criminal investigations unit in Miami.

He said the IRS is developing software “filters” to detect phony claims, but that the agency is also under constant pressure to issue refunds as quickly as possible to legitimate filers. “We have to be careful and not delay refunds to innocent taxpayers,” he said.

The twin problems of ID theft and tax fraud have become so widespread in the Internet age that an inspector general for the Treasury Department recently issued a report on the crisis. The report found the IRS paid out more than $5.2 billion in tax refunds to fraudsters who filed about 1.5 million fake returns using the stolen identities of other people. The report predicted that scammers are likely to swindle $21 billion more from the IRS over the next five years.