Chapel Hill, N.C. — Twenty catalytic converters have been stolen in the past week from cars in University of North Carolina park-and-ride lots, police said Friday.

The thefts are the latest in a string of crimes to get money from scrap metal. Dozens of metal vases disappeared from cemeteries in Wake and Johnston counties. Copper coils were ripped from air conditioning units, and hundreds of feet of copper cable that was stolen in Durham knocked out phone and Internet service to part of the city. Storm sewer grates were plucked from city streets.

Raleigh police said nine converters were stolen from vehicles at an automotive repair shop in the past month, and another five were taken from vehicles at a car dealership. Thirty-six converters have been reported stolen in Durham this year.

Catalytic converters are a part of a vehicle's exhaust system that help reduce harmful emissions. They contain small amounts of precious metals, including platinum, palladium and rhodium.

A converter was stolen out from under Richard Silc's vehicle on Tuesday. He uses a park-and-ride lot in Chatham County so he can take a bus to the UNC campus.

"I turn on the ignition (Tuesday evening) and hear this loud roar, and I immediately knew it was my catalytic converter," Silc said. "I've been through the drill before."

Last month, somebody tried to cut out his catalytic converter but didn't finish the job, he said.

"We have not seen the same kind of rash (of thefts) as we have over the past seven days," UNC Public Safety spokesman Randy Young said.

Replacing a stolen converter can cost hundreds of dollars. Silc said the estimate he received to repair his vehicle was almost $2,500.

Police urge people to be on the lookout for unusual behavior, especially in parking lots.

"(Watch for) people moving in and out from between cars (and) folks who are loitering in a parking lot, looking like they may be working on an automobile," Young said.

Silc said he would like to have cameras installed in commuter lots. UNC officials said they are exploring that option.

"I don't want to go through this again and the money and the hassle just to take public transportation," he said.