WORCESTER, Mass. - A Worcester auto repair shop is working with police after a specific car part was stolen from cars in their lot.

And it's not the first time its happened.

Over Labor Day weekend, Ramstrom's Service Center says someone took two catalytic converters from vehicles. The part is a crucial exhaust emissions control device, which converts toxic gases and pollutants into exhaust gas.

Owner Rick Ramstrom says they contain valuable precious metals and can cost anywhere from $800 to $3,000. He says the thieves work fast, and can cut them off in just minutes.

"They come in spurts. So what happens? You don't know. There are certain vehicles. They go after the trucks because they can roll right under a truck and cut it right off, they don't have to jack it up," Ramstrom said. "So you don't know. You come to work some mornings, you go out, you cross your fingers when you start the car up and say if the things sounds like a race car it's like 'Oh boy, they got us last night.'"

Ramstrom says it's helpful to have surveillance video, but says to get to the root of the problem, they need to find out where people are selling the stolen parts.