Federal law enforcement officials said yesterday that they have broken up three crime rings that staged car crashes in the Washington area, in which suspects deliberately collided with motorists and then defrauded insurance companies out of more than $1 million.

The technique, known as "swoop and squat," involves intentionally causing a crash, with one driver pulling his vehicle in front of another and slamming on the brakes, they said.

"Driving in this area is bad enough," U.S. Attorney Paul J. McNulty said. "The last thing we need is to suffer the threat of a roving band of criminals who are out to defraud the insurance company. . . . Literally everyone who drives is a potential victim."

The announcement was timed to coincide with the arrest of seven men on charges of mail fraud and conspiracy to commit interstate transport of stolen property.

Investigators said the men charged in the latest series of arrests are Walter Sonny Stevens, 41, of Charlotte; John R. Boley, 25, of Muncie, Ind.; Rockie W. Demitro, 25, of Arlington; Ricky Kastello, 26, of Falls Church; Rocky A. Kastello, 32, of Alexandria; and Santino J. Thompson, 19, and John Nicholas, 24, both of no known address.

Investigators said the men used false information to steal cars from a dealership in Anderson, Ind. They drove them to Northern Virginia, where they either intentionally damaged the cars by driving them into stationary objects or caused collisions with motorists. Officials said the men would then falsify insurance claims, collecting damages in excess of $300,000.

McNulty said the ring was initially detected during a routine traffic stop by an Arlington County police officer who was tipped off by fraudulent temporary tags on a car. It was later discovered that the car had been stolen from the Indiana dealership and had been involved in several crashes. Fairfax County police were working on a similar fraud investigation, and a joint federal task force was created.

Twenty people have been charged in connection with the Operation Moving Target initiative. Prosecutors said three crime rings have been brought down in the Washington area in the last six months by the task force. Similar schemes carried out nationwide have meant hundreds of millions of dollars in losses, they said.

In one common scheme, a member of the ring who has a legitimate car insurance policy files a false claim, admitting fault in a fake crash, while an accomplice acts as the claimant, calling the same insurance company seeking funds to fix his damaged car or restitution for injuries.

If the fraud goes undetected, the targeted insurer will settle the claim. Officials said the claimant often will not fix the car but will instead present the same car to multiple insurers.

Officials said that the rings get most of their money through fraudulent medical claims, alleging soft tissue injuries, which are difficult to disprove, and seeking care from disreputable health care providers who assist them in padding claims. Officials said the rings also use fake witnesses to corroborate the details of the fake crashes, as well as forged medical bills and receipts to document expenses.

Officials provided a photocopy of a forged medical bill that described hospital care that had allegedly been provided to a ring member: "Emergany Dept. Visit, Apply Arm Sprint."