There's a hot item that thieves across the Twin Cities are swiping from buses, cars, even semitrailer trucks.

So far this year, some police departments have seen an uptick in thefts of catalytic converters. The part, which controls emissions, can be sawed off and recycled for big money for its precious metals. It's been a target for auto thieves for decades, but now some police departments are seeing a resurgence in demand for the part.

In July, Minnetonka, Eden Prairie and Golden Valley police arrested two suspects who they say stole more than 200 catalytic converters in the metro area. In May, five vehicles in Maple Grove had the parts stolen. And in Blaine, the city has seen a rise in the thefts the past two years, with 16 catalytic converters stolen in May from one trucking company after a rash of thefts from cars at a park-and-ride in December.

"It's frustrating," Steven Ditschler said.

He's the CEO of ProAct Inc., a nonprofit that was the victim of thefts in Eagan earlier this year. Catalytic converters were stolen from three wheelchair-accessible buses and a van that transfers people with disabilities to employment centers.

The nonprofit relies on its fleet of 50 vans and buses for the service, so after the crime spree hit their business, Ditschler said they had to scramble to get other vehicles on a moment's notice.

"It's really disruptive. If you can't get there, you can't get them to the job sites," he said. "It's far more damaging than the value the thieves get out of the equipment. It's a ripple effect. Everything we do depends on vehicles. It impacts lives."

In St. Anthony, the city has had four thefts so far this year — up from only one reported theft last year.

The thefts all happened to business vehicles in an industrial area in January and February; one work truck's stolen catalytic converter was valued at $7,400, according to police.

While this kind of theft has taken place for decades, St. Anthony Police Capt. Dominic Cotroneo said scrap yards are doing a better job now of identifying stolen converters and reporting them to police.

Still, criminals can saw out the part quickly, sometimes in less than a minute, and get $500 or more for a catalytic converter, said Jeff Rodelius of Youngstedts Chanhassen Collision Center, adding he's heard of thieves targeting used car lots to raid multiple cars at once.

As soon as drivers start their vehicles, they'll know they've been hit.

"It's like you don't have an exhaust system in your car," he said. "You're going to know right away."

Unfortunately for both vehicle owners and police investigators, the crime is difficult to prevent — or predict.

"It goes in spurts; we won't see it, and then we will," said Hopkins Police Sgt. Mike Glassberg, adding that Hopkins has had six reported thefts so far this year. "It is definitely something that goes on continually. It's a hard one to catch, like most auto thefts."

Kelly Smith • 612-673-4141