Some unlucky Prius owners in San Francisco have been finding their Toyota hybrid cars distinctly less hybridized over the last few weeks, as thieves have taken to stealing the battery packs from their vehicles. According to San Francisco's KGO-TV, both police and dealerships in the area are aware of the growing trend, in which criminals smash the car's rear windows before cutting the cables connecting the battery and lifting it free from the trunk.

The batteries weigh about 120 pounds and reportedly take around an hour to remove by trained professionals, but according to police, the thieves have been able to remove them in around 20 minutes. It's not entirely clear what kickstarted the spate of battery thefts, but Yahoo Autos speculates the demand for the tech might be rising because first-generation Priuses, bought around a decade ago, are nearing the end of their battery warranties.

Replacements from official sources can cost up to $3,000, while second-hand batteries are a literal steal, reportedly going for under $1,000 on Craiglist. The lack of an identification number on hybrid batteries reduces the risk in stealing them, but if the thieves are boosting the batteries to sell to owners of older Toyota hybrids, they must be doing some extra work behind the scenes — according to Yahoo Autos, most of the stolen tech has come from the newest third-generation Prius, whose battery is not immediately compatible with first-generation models unless its cells are reassembled in a new housing.