What most astonished a Diamond Bar couple, even more than the brazenness of the driveway thieves, was their speed.
Security camera video shows two men jump out of an SUV, scramble underneath a parked Honda CRV, emerge with precious metals and take off.
"Literally two minutes," said David, the homeowner who preferred his last name not be shared. "We timed it."
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The precious metals -- including platinum and sometimes even gold -- are needed by a piece of pollution control equipment that has been standard in cars for decades -- the catalytic converter. It's located in the engine exhaust system.
Recycling the metals from one for scrap value can bring up to $200, and has made converters a target for thieves almost since first introduced.
"Had I been aware this was happening, I probably would have been more cautious," said David's wife Katia.
She discovered the theft hours later when she went out to her car and started the engine -- now much louder with a gap in the exhaust system where the converter used to be.
It happened at 3:30 a.m. on Sept. 23. Later, she learned from another resident in her neighborhood that half an hour later, thieves had also attempted to remove the catalytic converter from his car. He told her he heard them and yelled, and they took off without the converter, Katia said.
Both made crime reports with the Los Angeles County Sheriff's Walnut Station.
As in many households nowadays, garages are used for storage, and cars are parked in the driveway.
Dave and Katia's driveway was unlit, and on the security camera video it is not possible to make out the faces of the thieves, nor the license plate of their vehicle, which appears to be a full-size SUV with aftermarket rims. The team also included a driver who remained with the vehicle.
Since the theft, Katia and David have added a motion sensor light to illuminate the driveway.
By coincidence, Katia and her neighbor both took their targeted Hondas to the same garage, Vtec Auto Repair. Owner Oliver Lu said he all too often he sees cars from which the catalytic converters have been stolen.
Not long ago it happened to his mother-in-law's Toyota, he said.
For Katia's car, the insurance adjuster figured the loss at more than $2,700. The theft is covered by comprehensive insurance, but the policy holder is still responsible for the deductible.
The level of difficulty in removing catalytic converters varies widely among different auto models.
In the case of Katia's Honda model, the converter is held in place with five bolts that are easily accessed from underneath with a socket wrench. Other designs require cutting the exhaust pipe, and still others separate the converter into three separate units, one of which is accessible only by opening the hood.
The catalytic converter in V-6 Hondas are particularly well protected, said Lu, taking a reporter beneath an MDX on a hoist to show him. "This one you can't take off because it's part of the manifold itself."