Staged-accident gangs like the Massachusetts cabal have looted insurers and their policyholders around the United States for years. Nobody compiles data on how much insurance money these rings steal, but the toll likely exceeds $1 billion annually. The outfits are growing larger, more complex and, in some cases, more violent.

Densely populated states such as Massachusetts, California, Florida, New York and New Jersey are among the hardest-hit locales. Thus, they've become laboratories for fraud fighters to see what works.

Some states are farther along than others, but successful efforts have a common thread: highly focused shows of force, often involving several agencies working in tandem, and backed by get-tough fraud laws and courtroom tactics. It's a kind of gang tackle designed to inflict blunt-force trauma that intimidates and eviscerates these stubborn rings.

This is no small task. Marauding crash gangs can steal insurance money on an almost industrial scale. They try to overwhelm insurers by carpet bombing them with piles of complex claims for treating fake crash injuries. A least two small auto insurers in New York even went bankrupt after being targeted by gangs.

Rings typically pack cars with passengers--often recent immigrants who need the cash. Usually ring members ram their own cars into each other at low speeds.

But sometimes they target innocent motorists--especially women and seniors. The so-called passengers then pretend the crashes inflicted soft-tissue injuries, such as whiplash. They seek useless and overpriced treatment from crooked chiropractors, doctors, physical therapists, diagnostic clients and others in league with the swindles.

However, often the cars, crashes, passengers and treatment are solely on paper. Nothing is real except the stolen insurance money.

In Massachusetts, fraud fighters have launched task forces in 13 of the hardest-hit communities. Each Massachusetts task force combines the state fraud bureau, local police, insurers, state attorney general's office, local district attorneys and others.

More fraud investigators were also hired, including some fluent in Spanish. Billboards advertising the fraud bureau's fraud hotline in English and Spanish were erected along busy roadways. Chiropractors were required to post fraud warnings in their waiting rooms. The legislature also came down hard on gang recruiters (or "runners").

This show of force is working. More than 600 suspects have been charged since late 2003, with 65 convictions (so far) and more cases in the pipeline, the Massachusetts fraud bureau said.

Reported accidents and injury claims--common red flags of fraud--also have dropped sharply around the state. Total injury claims have dropped $345 million since 2002.

The savings are benefiting drivers. Auto premiums have fallen an average of 11.7 percent across the state this year, or $119 per driver. Average premiums have dropped fully 24 percent in Lawrence, one of the hardest-hit cities.

New York also ranks high among America's problem states, especially in the boroughs of New York City. Fake clinics are commonplace, and their only role is to make bogus claims. A grandmother even died when her car was rammed in a botched staged crash in Queens in 2003. Violent Russian and East European gangs also fiercely protect their turf.

The insurance department there has teamed with all 62 county prosecutors, plus insurer fraud units and local law enforcement. Special fraud prosecutors also go after rings directly. An auto-fraud unit was created in the attorney general's office.

Crash rings have put sunny California in a money-draining vise as well, especially in Southern California. A wide dragnet of state-local task forces is working there to grind down rings, targeting urban areas.

A novel courtroom tactic also is being used by Al MacKenzie, a Los Angeles County assistant district attorney. He's nailing ring members and other insurance crooks for tax fraud.

Mr. MacKenzie simply compares a suspect's reported income against the insurance money they actually received. Because swindlers don't report stolen insurance money to the state, he usually has a slam-dunk case of tax fraud, without building a complex insurance-fraud case.

New Jersey, meanwhile, has created an entire division to investigate and prosecute insurance swindles of all kinds--including staged crashes. A package of targeted fraud laws adds teeth. One reform will yank the license of medical providers convicted of any insurance swindle.

Florida is confronting its own fraud pandemic, especially in South Florida. Fraud fighters are close to being outgunned despite an energetic effort. Busts, convictions and case leads have risen sharply in recent years. Still, prosecutors and investigators struggle to handle the sheer volume of cases.

The state recently hired two prosecutors solely to roll up crash rings in South Florida. It's a welcome move, but much more help is needed. Fraud fighters were dealt a setback, however, when funding for added prosecutors and investigators fizzled in the legislature this spring.

Fortunately, Florida's lawmakers have passed tough laws that punish owners of crooked medical clinics, plus recruiters and kingpins for crash rings. So, at least solid courtroom tools are in place. Insurers also are betting that dumping the state's no-fault law this year will help remove the incentive for gangs to stage crashes.

Staged-crash rings likely will persist for years to come--the insurance money is too easy and profitable--but fraud fighters are learning what works. Often it boils down to coordinated shows of intimidating force involving multiple agencies.

But marshalling enough force--on the mean streets and in court rooms--requires considerable resources. Until a public groundswell of outrage compels the needed money, fraud fighters and crash rings will remain tightly hammer-locked. The only clear losers will be honest drivers who must pay higher auto premiums.