According to news reports, Miami-Dade police recently arrested a used car dealer and charged him with rolling back the odometer on a used 2101 Mazda CX9, erasing more than 81,000 miles.

Electronic odometers were supposed to make it harder for car dealers to cheat used car buyers by lopping miles off odometers. But the switch to electronic odometers just spawned a black market in odometer-tampering tools that are cheap and easy to buy online.

The multi-billion $$ fraud continues to plague used car buyers. In fact, it’s ridiculously easy for crooked car dealers to engage in odometer fraud, with little fear of getting caught.

The National Highway Traffic Safety Administration is tasked with policing odometer fraud, but the agency is chronically understaffed and under-funded, and seldom acts unless they find a widespread pattern of illegal rollbacks.

One of the worst impacts of odometer fraud: victims of the illegal practice often end up having to pay out of pocket for expensive, unanticipated repairs that can leave them deep in debt or without a car.

A double whammy — even if you buy an extended service contract, they usually exclude coverage for vehicles with altered odometers.

How can you avoid falling prey to crooked car dealers who alter odometers? Check out CARS’ tips for how to get a good deal on a safe, reliable used car, without having to set foot on a car dealer’s lot.

Read more: Miami Herald: “Miami car dealer rolled back 81,000 miles off odometer, cops say”