Twenty-one people have been charged with crimes in connection to a nationwide catalytic converter theft ring that raked in over half a billion dollars, the Department of Justice announced Wednesday.

The defendants were charged in two indictments in the Eastern District of California and the Northern District of Oklahoma. Millions of dollars in assets were seized across five states, according to a DOJ news release.

Catalytic converter thefts have skyrocketed in recent years, increasing by 325% between 2019 and 2020, according to the National Insurance Crime Bureau.

Part of a vehicle’s exhaust device, catalytic converters are often targets for theft because of the valuable precious metals in their centers and the speed at which they can be stolen – less than one minute, according to the DOJ. Catalytic converters also often lack identifying markings, making it difficult to trace a stolen converter back to its owner.

The black-market price for catalytic converters can be more than $1,000 each, the DOJ said.

California, in particular, has become a “hot bed” for catalytic converter theft, said U.S. Attorney Phillip A. Talbert for the Eastern District of California.

“Last year approximately 1,600 catalytic converters were reportedly stolen in California each month, and California accounts for 37% of all catalytic converter theft claims nationwide,” Talbert said in the release.

Nine defendants were charged in California with conspiracy to transport stolen catalytic converters, conspiracy to commit money laundering, and other charges related to the theft ring. 

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Among those charged were three people who allegedly bought stolen catalytic converters and sold over $38 million worth to an auto shop in New Jersey, according to the Department of Justice.

The shop “knowingly purchased stolen catalytic converters and extracted the precious metal powders from their centers,” according to the DOJ. The auto shop made over $545 million from the metal powders processed from California alone.

The defendants charged in Oklahoma shipped stolen catalytic converters to the same New Jersey shop, according to court documents. Three of the 13 defendants received over $64 million in wired funds from the auto shop.

One defendant was charged in both states, court documents show.

“This national network of criminals hurt victims across the country,” FBI Director Christopher Wray said in the release. “They made hundreds of millions of dollars in the process – on the backs of thousands of innocent car owners.”