That’s local attorney Peter Davis describing his daughter’s discovery that her 2007 Honda Element had lost a surprisingly valuable part while parked overnight outside her apartment in Arbor Landings Apartments: someone had stolen its catalytic converter.

In a December post on nextdoor.com, Davis wrote that they waited more than a month for replacement parts to come in at Germain Honda. They weren’t alone: at times, the dealership had as many as half a dozen vehicles waiting for converters. His daughter’s bill–fully covered by insurance–came to $5,207.70.

Catalytic converter thefts jumped 76 percent in Ann Arbor last year, reports AAPD detective bureau lieutenant Bonnie Theil, from twenty-five to forty-four. By mid-February, five more Ann Arborites had suffered their own noisy introductions to this global crime trend.

Few people think twice about their catalytic converters, a metal canister located ahead of the muffler. The devices, which clean emissions from the engine, have been standard on most vehicles sold in the U.S, since 1975. What’s their recent appeal to thieves?

The criminals are after the precious metals inside the devices, such as platinum, palladium, and rhodium, which combine to remove toxic chemicals from exhaust. According to the New York Times, the price of palladium is hovering between $2,000 and $2,500 an ounce, from about $500 an ounce five years ago. Rhodium has jumped thirty-fold, to a record $21,900 per ounce.

The price surge is driven by demand from China, which tightened emissions standards in 2016 and again last year. Enterprising thieves have responded by “mining” the minerals from exhaust systems. National data isn’t available, but rashes of catalytic converter thefts have been reported everywhere from California to Massachusetts, and Davis found similar stories from Great Britain.

With the right tools, a catalytic converter can be removed in minutes. The thief slides under the vehicle and removes the bolts holding the converter, or uses a cordless power saw to cut it off. Rogue scrap yards pay between $200 and $300 for the devices, take them apart, and sell the precious metals to recyclers for even more.

The AAPD’s Theil says thieves focus on older vehicles, often Japanese models, which have a reputation for using a better grade of metals. The Toyota Prius hybrid is especially prized, because the gasoline engine is only in use part of the time. That leaves the precious metals cleaner and more valuable to scrappers.

Hondas, including the Accord, CRV, Civic, and Element, are most frequently targeted in Ann Arbor, Theil says. Many of the incidents occur on open parking lots, such as those in apartment complexes, near hotels, and outside office buildings, she says.

That’s what happened to insurance adjuster Craig Trombley. Last March, thieves targeted his fleet of three Honda Elements sitting on the lot behind his office on Pauline Blvd. He likes the crossover SUVs’ roominess; thieves like their higher ground clearance, which makes the converter easier to snip.

The bandits made off with two catalytic converters. A third, protected by an anti-theft device, was damaged. Like Davis’s daughter, he knew right away that he’d been hit: “You get in your car, and it’s so loud it sounds like a car without a muffler,” he says.

Trombley says it cost $3,200 apiece to have his converters replaced. He thinks Ann Arbor police should be doing more to catch the culprits. “This is a crime of opportunity,” he says. “If this was a party store or a bank, they’d be putting a lot more effort into it.”

The replacement converters use a lower level of rare metals, so they’re less tempting targets. Nevertheless, Trombley has since installed anti-theft devices to protect them as well.

Installed by a shop in Toledo, they’re essentially a cage that goes over the converter, with cables securing it in place.