Peter Fitts had mixed emotions this week when he learned that Augusta police had arrested someone in connection with the thefts of 11 catalytic converters from cars parked at his auto shop.

On one hand, Fitts is glad to see someone charged.

On the other, he’s still left with a handful of cars that sound like something you’d hear at Unity Raceway.

“I filed the claim and then withdrew it because they brought back the converters,” said Fitts, owner of Independent Auto on Riverside Drive in Augusta. “It still represents a significant amount of damage. It’s not as if I can throw them back on.”

Stephen F. Ivanusic, 45, formerly of Augusta and now living in Saco, was charged with four felony counts of theft by unauthorized taking in connection with the thefts.

Ivanusic was charged Aug. 6 at York County Jail, where he was being held on unrelated charges, Augusta police Detective Jason Cote announced Tuesday.

Cote said this week the investigation is ongoing. Additional charges are expected in connection with converter thefts in other communities.

Cote said Ivanusic confessed to stealing catalytic converters from vehicles in several towns. In addition to the 11 thefts from Fitts’ Independent Auto, Ivanusic is charged with stealing two converters from vehicles at Charlie’s Toyota on Western Avenue and one from Lee’s Credit Express, also on Western Avenue.

The thefts took place between June 24 and July 17. The devices were all cut from the vehicles using an exhaust pipe cutter, Cote said.

Local and regional police have received numerous reports of catalytic converter thefts from throughout the Augusta region over the past several weeks. Those reports include four from Main Street in Richmond on July 28 and one from Gary’s Good Deals in Randolph on July 27.

The Randolph theft “appears to be related to several other catalytic converter thefts in the Kennebec County area,” Maine State Police Lt. David Tripp said at the time, adding: “Catalytic converter thefts have been on the rise the last couple of years.”

Mandated as a pollution control mechanism in the United States since 1975, catalytic converters are attractive to thieves because they contain precious metals such as platinum, palladium, rhodium or gold to process and remove harmful pollutants.

Depending on the metal contained inside, catalytic converters can fetch $20 to $200 at metal recycling centers, according to the car-buying guide Edmunds.com.

Thieves often cut the converters from the exhaust system in just a few minutes, according to Edmunds, and the theft most often goes undetected until the owner starts the car and hears the unmistakable roar.

At an auto dealership, where cars may not be started for days at a time, thieves can have a significant amount of time to pawn their products without raising suspicion, police say.

Replacing the converter can cost more than $2,000, said Gary Pratt, owner of Gary’s Good Deals Sales & Service on Water Street in Randolph.

Thieves stole converters off two of Pratt’s vehicles last month. Both were Toyota Tacomas, a popular target of catalytic converter thieves.

“The foreign stuff is worth more than the American stuff,” Pratt said.

Pratt discovered one of the thefts when he started the truck for a potential buyer to test drive.

“I listed a $500 reward on Craig’s List to find out who did it,” Pratt said. “I never got one call.”

While on Craigslist, an Internet classified site, Pratt discovered people are now also selling oxygen sensors, which are often located near the catalytic converter. He believes thieves are now taking both the converter and sensor, which leads to even greater replacement costs.

“I didn’t know they did that until I saw that ad on Craigslist,” Pratt said.

Pratt has added more lighting and cameras and said other dealers are doing the same.

“Two days ago I put in a motion detector light and it’s 500 watts,” he said.

Augusta police Sgt. Christopher Massey said parking in well-lit areas can make vehicles less attractive to would-be thieves.

There is also a device called the CatClamp that encloses the converter in a cage, making it less accessible. The clamps start at about $150.

Massey said the public, too, can play a role in cutting down on the number of thefts, simply by being vigilant.

If you see people lurking around vehicles, particularly in dealership parking lots, call police, Massey said.

“It’s not uncommon after dark to see people driving through a dealership, but it’s not common at 1:30 a.m.,” Massey said. “If you’re out and about, and you see people in the early morning hours, call us.”

Fitts, meanwhile, is still working to replace the converters stolen from cars that belonged to customers. He said each of the repairs will cost him about $500, not including his labor.

“I’m not looking to profit from this,” he said. “I’ve got great customers.”