A rash of catalytic converter thefts appears to be intensifying in Washtenaw County.

Over the weekend, catalytic converters have been stolen in Ann Arbor, Pittsfield Township and on the University of Michigan campus.

On Saturday, catalytic converters were stolen throughout the Glencoe Hills apartment complex, Pittsfield Township police said. On Thursday, converters were taken off three vehicles at Weatherstone Condominiums in Pittsfield Township.

A catalytic converter.

Police say the thefts appear tied to a recent increase in the value of metal. Thieves use a cordless saw to cut the exhaust pipe to quickly remove the catalytic converters.

Michigan State Police Sgt. Tony Cuevas said victims usually realize what happened because the exhaust pipe will drag or make loud noises.

Cuevas said state police haven't seen the recent increase, and Ypsilanti police said catalytic converters haven't been stolen in recent days in the city.

But Ann Arbor police say they took several reports of catalytic converter thefts on Friday. At at least four such thefts were reported over the weekend on the U-M campus, including three on Saturday.

According to the U-M crime log, cars were parked on Cram Place and Beal Street when the converters were stolen sometime over the last several days. Earlier last week, at least two other catalytic converter thefts were reported at U-M.

Each converter was valued at $300, though officials say replacing them can cost about $1,000. In addition, vehicles are sometimes damaged when the catalytic converter is taken.

The catalytic converter is used to convert harmful pollutants into less harmful emissions before they leave the exhaust system. It's located in the car's exhaust system, and precious metals such as platinum, palladium, rhodium or gold are used as the catalyst.

Police say thieves sell the converters to metal recyclers, who then extract the metal and resell it.

Unfortunately, police say, there are few precautions owners can take to protect the catalytic converter from being stolen.