OMAHA - Kim Muffly walked to her car early one recent afternoon. Though it had been a shorter-than-normal shift at her job as a nurse at the Nebraska Medical Center, she was glad to be going home.

She got into her Toyota 4Runner and turned the key. A deafening roar rattled the vehicle.

"It sounded worse than having a hole in your muffler. It was the loudest noise,'' she said. "It sounded like a big old hot rod.''

She got out and looked under her vehicle. A piece of the exhaust system was missing.

Muffly was a victim in the latest trend in petty crime in Omaha and nationwide: the theft of catalytic converters.

Thieves steal the devices, which convert harmful gases to less toxic gases, for the three metals the converters contain: rhodium, platinum and palladium. Omaha police say thieves can get about $45 per converter at scrap yards.

At the beginning of February, rhodium was trading at $7,260 per ounce, compared to $5,350 a year before. Platinum was at $1,756 per ounce, compared to $1,178 a year before, and palladium was trading at $411 per ounce, compared to $343 a year before, according to the Web site Kitco, a precious metal retailer.

Omaha Police Department spokesman David Spizzirri said the department's crime analysis unit collects the salvage tickets filled out when somebody brings an item into a salvage yard. Those selling the items must present identification, and their fingerprints are taken.

At least three catalytic converters were reported stolen in Omaha in early January.

Omaha isn't alone. Other cities, including Flint, Mich., Jackson, Miss., and Minneapolis, have reported thefts of catalytic converters.

The devices on 4Runners like Muffly's are frequently targeted because of their high ground clearance. The converters are cut or unbolted from the exhaust systems.

In January, Chicago police arrested four people after they caught a man underneath a Toyota sedan with a battery-powered saw.

Spizzirri recommended that motorists park in well-lit areas to avoid being victimized.

That didn't help Muffly, who parks in a busy lot in mostly daylight hours. "It's surrounded by Farnam, Harney and 42nd Street, and there's people driving into that parking lot pretty frequently,'' she said.

Muffly drove home -- loudly -- and called a Toyota dealer, which installed another catalytic converter for $290.

"I'm kind of disgusted, I guess, plus the part that I have to go back and park at the same place,'' she said. "I'm just hoping it doesn't happen again.''